---
_id: '302'
abstract:
- lang: eng
text: At ITCS 2013, Mahmoody, Moran and Vadhan [MMV13] introduce and construct publicly
verifiable proofs of sequential work, which is a protocol for proving that one
spent sequential computational work related to some statement. The original motivation
for such proofs included non-interactive time-stamping and universally verifiable
CPU benchmarks. A more recent application, and our main motivation, are blockchain
designs, where proofs of sequential work can be used – in combination with proofs
of space – as a more ecological and economical substitute for proofs of work which
are currently used to secure Bitcoin and other cryptocurrencies. The construction
proposed by [MMV13] is based on a hash function and can be proven secure in the
random oracle model, or assuming inherently sequential hash-functions, which is
a new standard model assumption introduced in their work. In a proof of sequential
work, a prover gets a “statement” χ, a time parameter N and access to a hash-function
H, which for the security proof is modelled as a random oracle. Correctness requires
that an honest prover can make a verifier accept making only N queries to H, while
soundness requires that any prover who makes the verifier accept must have made
(almost) N sequential queries to H. Thus a solution constitutes a proof that N
time passed since χ was received. Solutions must be publicly verifiable in time
at most polylogarithmic in N. The construction of [MMV13] is based on “depth-robust”
graphs, and as a consequence has rather poor concrete parameters. But the major
drawback is that the prover needs not just N time, but also N space to compute
a proof. In this work we propose a proof of sequential work which is much simpler,
more efficient and achieves much better concrete bounds. Most importantly, the
space required can be as small as log (N) (but we get better soundness using slightly
more memory than that). An open problem stated by [MMV13] that our construction
does not solve either is achieving a “unique” proof, where even a cheating prover
can only generate a single accepting proof. This property would be extremely useful
for applications to blockchains.
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Bram
full_name: Cohen, Bram
last_name: Cohen
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Cohen B, Pietrzak KZ. Simple proofs of sequential work. In: Vol 10821. Springer;
2018:451-467. doi:10.1007/978-3-319-78375-8_15'
apa: 'Cohen, B., & Pietrzak, K. Z. (2018). Simple proofs of sequential work
(Vol. 10821, pp. 451–467). Presented at the Eurocrypt: Advances in Cryptology,
Tel Aviv, Israel: Springer. https://doi.org/10.1007/978-3-319-78375-8_15'
chicago: Cohen, Bram, and Krzysztof Z Pietrzak. “Simple Proofs of Sequential Work,”
10821:451–67. Springer, 2018. https://doi.org/10.1007/978-3-319-78375-8_15.
ieee: 'B. Cohen and K. Z. Pietrzak, “Simple proofs of sequential work,” presented
at the Eurocrypt: Advances in Cryptology, Tel Aviv, Israel, 2018, vol. 10821,
pp. 451–467.'
ista: 'Cohen B, Pietrzak KZ. 2018. Simple proofs of sequential work. Eurocrypt:
Advances in Cryptology, LNCS, vol. 10821, 451–467.'
mla: Cohen, Bram, and Krzysztof Z. Pietrzak. Simple Proofs of Sequential Work.
Vol. 10821, Springer, 2018, pp. 451–67, doi:10.1007/978-3-319-78375-8_15.
short: B. Cohen, K.Z. Pietrzak, in:, Springer, 2018, pp. 451–467.
conference:
end_date: 2018-05-03
location: Tel Aviv, Israel
name: 'Eurocrypt: Advances in Cryptology'
start_date: 2018-04-29
date_created: 2018-12-11T11:45:42Z
date_published: 2018-05-29T00:00:00Z
date_updated: 2023-09-18T09:29:33Z
day: '29'
department:
- _id: KrPi
doi: 10.1007/978-3-319-78375-8_15
ec_funded: 1
external_id:
isi:
- '000517098700015'
intvolume: ' 10821'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2018/183.pdf
month: '05'
oa: 1
oa_version: Submitted Version
page: 451 - 467
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_status: published
publisher: Springer
publist_id: '7579'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Simple proofs of sequential work
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 10821
year: '2018'
...
---
_id: '298'
abstract:
- lang: eng
text: "Memory-hard functions (MHF) are functions whose evaluation cost is dominated
by memory cost. MHFs are egalitarian, in the sense that evaluating them on dedicated
hardware (like FPGAs or ASICs) is not much cheaper than on off-the-shelf hardware
(like x86 CPUs). MHFs have interesting cryptographic applications, most notably
to password hashing and securing blockchains.\r\n\r\nAlwen and Serbinenko [STOC’15]
define the cumulative memory complexity (cmc) of a function as the sum (over all
time-steps) of the amount of memory required to compute the function. They advocate
that a good MHF must have high cmc. Unlike previous notions, cmc takes into account
that dedicated hardware might exploit amortization and parallelism. Still, cmc
has been critizised as insufficient, as it fails to capture possible time-memory
trade-offs; as memory cost doesn’t scale linearly, functions with the same cmc
could still have very different actual hardware cost.\r\n\r\nIn this work we address
this problem, and introduce the notion of sustained-memory complexity, which requires
that any algorithm evaluating the function must use a large amount of memory for
many steps. We construct functions (in the parallel random oracle model) whose
sustained-memory complexity is almost optimal: our function can be evaluated using
n steps and O(n/log(n)) memory, in each step making one query to the (fixed-input
length) random oracle, while any algorithm that can make arbitrary many parallel
queries to the random oracle, still needs Ω(n/log(n)) memory for Ω(n) steps.\r\n\r\nAs
has been done for various notions (including cmc) before, we reduce the task of
constructing an MHFs with high sustained-memory complexity to proving pebbling
lower bounds on DAGs. Our main technical contribution is the construction is a
family of DAGs on n nodes with constant indegree with high “sustained-space complexity”,
meaning that any parallel black-pebbling strategy requires Ω(n/log(n)) pebbles
for at least Ω(n) steps.\r\n\r\nAlong the way we construct a family of maximally
“depth-robust” DAGs with maximum indegree O(logn) , improving upon the construction
of Mahmoody et al. [ITCS’13] which had maximum indegree O(log2n⋅"
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Jeremiah
full_name: Blocki, Jeremiah
last_name: Blocki
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Alwen JF, Blocki J, Pietrzak KZ. Sustained space complexity. In: Vol 10821.
Springer; 2018:99-130. doi:10.1007/978-3-319-78375-8_4'
apa: 'Alwen, J. F., Blocki, J., & Pietrzak, K. Z. (2018). Sustained space complexity
(Vol. 10821, pp. 99–130). Presented at the Eurocrypt 2018: Advances in Cryptology,
Tel Aviv, Israel: Springer. https://doi.org/10.1007/978-3-319-78375-8_4'
chicago: Alwen, Joel F, Jeremiah Blocki, and Krzysztof Z Pietrzak. “Sustained Space
Complexity,” 10821:99–130. Springer, 2018. https://doi.org/10.1007/978-3-319-78375-8_4.
ieee: 'J. F. Alwen, J. Blocki, and K. Z. Pietrzak, “Sustained space complexity,”
presented at the Eurocrypt 2018: Advances in Cryptology, Tel Aviv, Israel, 2018,
vol. 10821, pp. 99–130.'
ista: 'Alwen JF, Blocki J, Pietrzak KZ. 2018. Sustained space complexity. Eurocrypt
2018: Advances in Cryptology, LNCS, vol. 10821, 99–130.'
mla: Alwen, Joel F., et al. Sustained Space Complexity. Vol. 10821, Springer,
2018, pp. 99–130, doi:10.1007/978-3-319-78375-8_4.
short: J.F. Alwen, J. Blocki, K.Z. Pietrzak, in:, Springer, 2018, pp. 99–130.
conference:
end_date: 2018-05-03
location: Tel Aviv, Israel
name: 'Eurocrypt 2018: Advances in Cryptology'
start_date: 2018-04-29
date_created: 2018-12-11T11:45:41Z
date_published: 2018-03-31T00:00:00Z
date_updated: 2023-09-19T09:59:30Z
day: '31'
department:
- _id: KrPi
doi: 10.1007/978-3-319-78375-8_4
ec_funded: 1
external_id:
arxiv:
- '1705.05313'
isi:
- '000517098700004'
intvolume: ' 10821'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1705.05313
month: '03'
oa: 1
oa_version: Preprint
page: 99 - 130
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_status: published
publisher: Springer
publist_id: '7583'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Sustained space complexity
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 10821
year: '2018'
...
---
_id: '5980'
abstract:
- lang: eng
text: The problem of private set-intersection (PSI) has been traditionally treated
as an instance of the more general problem of multi-party computation (MPC). Consequently,
in order to argue security, or compose these protocols one has to rely on the
general theory that was developed for the purpose of MPC. The pursuit of efficient
protocols, however, has resulted in designs that exploit properties pertaining
to PSI. In almost all practical applications where a PSI protocol is deployed,
it is expected to be executed multiple times, possibly on related inputs. In this
work we initiate a dedicated study of PSI in the multi-interaction (MI) setting.
In this model a server sets up the common system parameters and executes set-intersection
multiple times with potentially different clients. We discuss a few attacks that
arise when protocols are naïvely composed in this manner and, accordingly, craft
security definitions for the MI setting and study their inter-relation. Finally,
we suggest a set of protocols that are MI-secure, at the same time almost as efficient
as their parent, stand-alone, protocols.
article_processing_charge: No
author:
- first_name: Sanjit
full_name: Chatterjee, Sanjit
last_name: Chatterjee
- first_name: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
- first_name: Vikas
full_name: Kumar, Vikas
last_name: Kumar
citation:
ama: Chatterjee S, Kamath Hosdurg C, Kumar V. Private set-intersection with common
set-up. American Institute of Mathematical Sciences. 2018;12(1):17-47.
doi:10.3934/amc.2018002
apa: Chatterjee, S., Kamath Hosdurg, C., & Kumar, V. (2018). Private set-intersection
with common set-up. American Institute of Mathematical Sciences. AIMS.
https://doi.org/10.3934/amc.2018002
chicago: Chatterjee, Sanjit, Chethan Kamath Hosdurg, and Vikas Kumar. “Private Set-Intersection
with Common Set-Up.” American Institute of Mathematical Sciences. AIMS,
2018. https://doi.org/10.3934/amc.2018002.
ieee: S. Chatterjee, C. Kamath Hosdurg, and V. Kumar, “Private set-intersection
with common set-up,” American Institute of Mathematical Sciences, vol.
12, no. 1. AIMS, pp. 17–47, 2018.
ista: Chatterjee S, Kamath Hosdurg C, Kumar V. 2018. Private set-intersection with
common set-up. American Institute of Mathematical Sciences. 12(1), 17–47.
mla: Chatterjee, Sanjit, et al. “Private Set-Intersection with Common Set-Up.” American
Institute of Mathematical Sciences, vol. 12, no. 1, AIMS, 2018, pp. 17–47,
doi:10.3934/amc.2018002.
short: S. Chatterjee, C. Kamath Hosdurg, V. Kumar, American Institute of Mathematical
Sciences 12 (2018) 17–47.
date_created: 2019-02-13T13:49:41Z
date_published: 2018-02-01T00:00:00Z
date_updated: 2023-09-19T14:27:59Z
day: '01'
department:
- _id: KrPi
doi: 10.3934/amc.2018002
external_id:
isi:
- '000430950400002'
intvolume: ' 12'
isi: 1
issue: '1'
language:
- iso: eng
month: '02'
oa_version: None
page: 17-47
publication: American Institute of Mathematical Sciences
publication_status: published
publisher: AIMS
quality_controlled: '1'
scopus_import: '1'
status: public
title: Private set-intersection with common set-up
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 12
year: '2018'
...
---
_id: '6941'
abstract:
- lang: eng
text: "Bitcoin has become the most successful cryptocurrency ever deployed, and
its most distinctive feature is that it is decentralized. Its underlying protocol
(Nakamoto consensus) achieves this by using proof of work, which has the drawback
that it causes the consumption of vast amounts of energy to maintain the ledger.
Moreover, Bitcoin mining dynamics have become less distributed over time.\r\n\r\nTowards
addressing these issues, we propose SpaceMint, a cryptocurrency based on proofs
of space instead of proofs of work. Miners in SpaceMint dedicate disk space rather
than computation. We argue that SpaceMint’s design solves or alleviates several
of Bitcoin’s issues: most notably, its large energy consumption. SpaceMint also
rewards smaller miners fairly according to their contribution to the network,
thus incentivizing more distributed participation.\r\n\r\nThis paper adapts proof
of space to enable its use in cryptocurrency, studies the attacks that can arise
against a Bitcoin-like blockchain that uses proof of space, and proposes a new
blockchain format and transaction types to address these attacks. Our prototype
shows that initializing 1 TB for mining takes about a day (a one-off setup cost),
and miners spend on average just a fraction of a second per block mined. Finally,
we provide a game-theoretic analysis modeling SpaceMint as an extensive game (the
canonical game-theoretic notion for games that take place over time) and show
that this stylized game satisfies a strong equilibrium notion, thereby arguing
for SpaceMint ’s stability and consensus."
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Sunoo
full_name: Park, Sunoo
last_name: Park
- first_name: Albert
full_name: Kwon, Albert
last_name: Kwon
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Park S, Kwon A, Fuchsbauer G, Gazi P, Alwen JF, Pietrzak KZ. SpaceMint: A
cryptocurrency based on proofs of space. In: 22nd International Conference
on Financial Cryptography and Data Security. Vol 10957. Springer Nature; 2018:480-499.
doi:10.1007/978-3-662-58387-6_26'
apa: 'Park, S., Kwon, A., Fuchsbauer, G., Gazi, P., Alwen, J. F., & Pietrzak,
K. Z. (2018). SpaceMint: A cryptocurrency based on proofs of space. In 22nd
International Conference on Financial Cryptography and Data Security (Vol.
10957, pp. 480–499). Nieuwpoort, Curacao: Springer Nature. https://doi.org/10.1007/978-3-662-58387-6_26'
chicago: 'Park, Sunoo, Albert Kwon, Georg Fuchsbauer, Peter Gazi, Joel F Alwen,
and Krzysztof Z Pietrzak. “SpaceMint: A Cryptocurrency Based on Proofs of Space.”
In 22nd International Conference on Financial Cryptography and Data Security,
10957:480–99. Springer Nature, 2018. https://doi.org/10.1007/978-3-662-58387-6_26.'
ieee: 'S. Park, A. Kwon, G. Fuchsbauer, P. Gazi, J. F. Alwen, and K. Z. Pietrzak,
“SpaceMint: A cryptocurrency based on proofs of space,” in 22nd International
Conference on Financial Cryptography and Data Security, Nieuwpoort, Curacao,
2018, vol. 10957, pp. 480–499.'
ista: 'Park S, Kwon A, Fuchsbauer G, Gazi P, Alwen JF, Pietrzak KZ. 2018. SpaceMint:
A cryptocurrency based on proofs of space. 22nd International Conference on Financial
Cryptography and Data Security. FC: Financial Cryptography and Data Security,
LNCS, vol. 10957, 480–499.'
mla: 'Park, Sunoo, et al. “SpaceMint: A Cryptocurrency Based on Proofs of Space.”
22nd International Conference on Financial Cryptography and Data Security,
vol. 10957, Springer Nature, 2018, pp. 480–99, doi:10.1007/978-3-662-58387-6_26.'
short: S. Park, A. Kwon, G. Fuchsbauer, P. Gazi, J.F. Alwen, K.Z. Pietrzak, in:,
22nd International Conference on Financial Cryptography and Data Security, Springer
Nature, 2018, pp. 480–499.
conference:
end_date: 2018-03-02
location: Nieuwpoort, Curacao
name: 'FC: Financial Cryptography and Data Security'
start_date: 2018-02-26
date_created: 2019-10-14T06:35:38Z
date_published: 2018-12-07T00:00:00Z
date_updated: 2023-09-19T15:02:13Z
day: '07'
department:
- _id: KrPi
doi: 10.1007/978-3-662-58387-6_26
ec_funded: 1
external_id:
isi:
- '000540656400026'
intvolume: ' 10957'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2015/528
month: '12'
oa: 1
oa_version: Submitted Version
page: 480-499
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication: 22nd International Conference on Financial Cryptography and Data Security
publication_identifier:
eissn:
- 1611-3349
isbn:
- '9783662583869'
- '9783662583876'
issn:
- 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'SpaceMint: A cryptocurrency based on proofs of space'
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 10957
year: '2018'
...
---
_id: '1175'
abstract:
- lang: eng
text: We study space complexity and time-space trade-offs with a focus not on peak
memory usage but on overall memory consumption throughout the computation. Such
a cumulative space measure was introduced for the computational model of parallel
black pebbling by [Alwen and Serbinenko ’15] as a tool for obtaining results in
cryptography. We consider instead the non- deterministic black-white pebble game
and prove optimal cumulative space lower bounds and trade-offs, where in order
to minimize pebbling time the space has to remain large during a significant fraction
of the pebbling. We also initiate the study of cumulative space in proof complexity,
an area where other space complexity measures have been extensively studied during
the last 10–15 years. Using and extending the connection between proof complexity
and pebble games in [Ben-Sasson and Nordström ’08, ’11] we obtain several strong
cumulative space results for (even parallel versions of) the resolution proof
system, and outline some possible future directions of study of this, in our opinion,
natural and interesting space measure.
alternative_title:
- LIPIcs
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Susanna
full_name: De Rezende, Susanna
last_name: De Rezende
- first_name: Jakob
full_name: Nordstrom, Jakob
last_name: Nordstrom
- first_name: Marc
full_name: Vinyals, Marc
last_name: Vinyals
citation:
ama: 'Alwen JF, De Rezende S, Nordstrom J, Vinyals M. Cumulative space in black-white
pebbling and resolution. In: Papadimitriou C, ed. Vol 67. Schloss Dagstuhl - Leibniz-Zentrum
für Informatik; 2017:38:1-38-21. doi:10.4230/LIPIcs.ITCS.2017.38'
apa: 'Alwen, J. F., De Rezende, S., Nordstrom, J., & Vinyals, M. (2017). Cumulative
space in black-white pebbling and resolution. In C. Papadimitriou (Ed.) (Vol.
67, p. 38:1-38-21). Presented at the ITCS: Innovations in Theoretical Computer
Science, Berkeley, CA, United States: Schloss Dagstuhl - Leibniz-Zentrum für Informatik.
https://doi.org/10.4230/LIPIcs.ITCS.2017.38'
chicago: Alwen, Joel F, Susanna De Rezende, Jakob Nordstrom, and Marc Vinyals. “Cumulative
Space in Black-White Pebbling and Resolution.” edited by Christos Papadimitriou,
67:38:1-38-21. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017. https://doi.org/10.4230/LIPIcs.ITCS.2017.38.
ieee: 'J. F. Alwen, S. De Rezende, J. Nordstrom, and M. Vinyals, “Cumulative space
in black-white pebbling and resolution,” presented at the ITCS: Innovations in
Theoretical Computer Science, Berkeley, CA, United States, 2017, vol. 67, p. 38:1-38-21.'
ista: 'Alwen JF, De Rezende S, Nordstrom J, Vinyals M. 2017. Cumulative space in
black-white pebbling and resolution. ITCS: Innovations in Theoretical Computer
Science, LIPIcs, vol. 67, 38:1-38-21.'
mla: Alwen, Joel F., et al. Cumulative Space in Black-White Pebbling and Resolution.
Edited by Christos Papadimitriou, vol. 67, Schloss Dagstuhl - Leibniz-Zentrum
für Informatik, 2017, p. 38:1-38-21, doi:10.4230/LIPIcs.ITCS.2017.38.
short: J.F. Alwen, S. De Rezende, J. Nordstrom, M. Vinyals, in:, C. Papadimitriou
(Ed.), Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017, p. 38:1-38-21.
conference:
end_date: 2017-01-11
location: Berkeley, CA, United States
name: 'ITCS: Innovations in Theoretical Computer Science'
start_date: 2017-01-09
date_created: 2018-12-11T11:50:33Z
date_published: 2017-01-01T00:00:00Z
date_updated: 2021-01-12T06:48:51Z
day: '01'
ddc:
- '005'
- '600'
department:
- _id: KrPi
doi: 10.4230/LIPIcs.ITCS.2017.38
editor:
- first_name: Christos
full_name: Papadimitriou, Christos
last_name: Papadimitriou
file:
- access_level: open_access
checksum: dbc94810be07c2fb1945d5c2a6130e6c
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:17:11Z
date_updated: 2020-07-14T12:44:37Z
file_id: '5263'
file_name: IST-2018-927-v1+1_LIPIcs-ITCS-2017-38.pdf
file_size: 557769
relation: main_file
file_date_updated: 2020-07-14T12:44:37Z
has_accepted_license: '1'
intvolume: ' 67'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
page: 38:1-38-21
publication_identifier:
issn:
- '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
publist_id: '6179'
pubrep_id: '927'
quality_controlled: '1'
scopus_import: 1
status: public
title: Cumulative space in black-white pebbling and resolution
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 67
year: '2017'
...
---
_id: '605'
abstract:
- lang: eng
text: 'Position based cryptography (PBC), proposed in the seminal work of Chandran,
Goyal, Moriarty, and Ostrovsky (SIAM J. Computing, 2014), aims at constructing
cryptographic schemes in which the identity of the user is his geographic position.
Chandran et al. construct PBC schemes for secure positioning and position-based
key agreement in the bounded-storage model (Maurer, J. Cryptology, 1992). Apart
from bounded memory, their security proofs need a strong additional restriction
on the power of the adversary: he cannot compute joint functions of his inputs.
Removing this assumption is left as an open problem. We show that an answer to
this question would resolve a long standing open problem in multiparty communication
complexity: finding a function that is hard to compute with low communication
complexity in the simultaneous message model, but easy to compute in the fully
adaptive model. On a more positive side: we also show some implications in the
other direction, i.e.: we prove that lower bounds on the communication complexity
of certain multiparty problems imply existence of PBC primitives. Using this result
we then show two attractive ways to “bypass” our hardness result: the first uses
the random oracle model, the second weakens the locality requirement in the bounded-storage
model to online computability. The random oracle construction is arguably one
of the simplest proposed so far in this area. Our results indicate that constructing
improved provably secure protocols for PBC requires a better understanding of
multiparty communication complexity. This is yet another example where negative
results in one area (in our case: lower bounds in multiparty communication complexity)
can be used to construct secure cryptographic schemes.'
alternative_title:
- LNCS
author:
- first_name: Joshua
full_name: Brody, Joshua
last_name: Brody
- first_name: Stefan
full_name: Dziembowski, Stefan
last_name: Dziembowski
- first_name: Sebastian
full_name: Faust, Sebastian
last_name: Faust
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Brody J, Dziembowski S, Faust S, Pietrzak KZ. Position based cryptography
and multiparty communication complexity. In: Kalai Y, Reyzin L, eds. Vol 10677.
Springer; 2017:56-81. doi:10.1007/978-3-319-70500-2_3'
apa: 'Brody, J., Dziembowski, S., Faust, S., & Pietrzak, K. Z. (2017). Position
based cryptography and multiparty communication complexity. In Y. Kalai &
L. Reyzin (Eds.) (Vol. 10677, pp. 56–81). Presented at the TCC: Theory of Cryptography
Conference, Baltimore, MD, United States: Springer. https://doi.org/10.1007/978-3-319-70500-2_3'
chicago: Brody, Joshua, Stefan Dziembowski, Sebastian Faust, and Krzysztof Z Pietrzak.
“Position Based Cryptography and Multiparty Communication Complexity.” edited
by Yael Kalai and Leonid Reyzin, 10677:56–81. Springer, 2017. https://doi.org/10.1007/978-3-319-70500-2_3.
ieee: 'J. Brody, S. Dziembowski, S. Faust, and K. Z. Pietrzak, “Position based cryptography
and multiparty communication complexity,” presented at the TCC: Theory of Cryptography
Conference, Baltimore, MD, United States, 2017, vol. 10677, pp. 56–81.'
ista: 'Brody J, Dziembowski S, Faust S, Pietrzak KZ. 2017. Position based cryptography
and multiparty communication complexity. TCC: Theory of Cryptography Conference,
LNCS, vol. 10677, 56–81.'
mla: Brody, Joshua, et al. Position Based Cryptography and Multiparty Communication
Complexity. Edited by Yael Kalai and Leonid Reyzin, vol. 10677, Springer,
2017, pp. 56–81, doi:10.1007/978-3-319-70500-2_3.
short: J. Brody, S. Dziembowski, S. Faust, K.Z. Pietrzak, in:, Y. Kalai, L. Reyzin
(Eds.), Springer, 2017, pp. 56–81.
conference:
end_date: 2017-11-15
location: Baltimore, MD, United States
name: 'TCC: Theory of Cryptography Conference'
start_date: 2017-11-12
date_created: 2018-12-11T11:47:27Z
date_published: 2017-11-05T00:00:00Z
date_updated: 2021-01-12T08:05:53Z
day: '05'
department:
- _id: KrPi
doi: 10.1007/978-3-319-70500-2_3
ec_funded: 1
editor:
- first_name: Yael
full_name: Kalai, Yael
last_name: Kalai
- first_name: Leonid
full_name: Reyzin, Leonid
last_name: Reyzin
intvolume: ' 10677'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/536
month: '11'
oa: 1
oa_version: Submitted Version
page: 56 - 81
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
isbn:
- 978-331970499-9
publication_status: published
publisher: Springer
publist_id: '7200'
quality_controlled: '1'
scopus_import: 1
status: public
title: Position based cryptography and multiparty communication complexity
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 10677
year: '2017'
...
---
_id: '609'
abstract:
- lang: eng
text: Several cryptographic schemes and applications are based on functions that
are both reasonably efficient to compute and moderately hard to invert, including
client puzzles for Denial-of-Service protection, password protection via salted
hashes, or recent proof-of-work blockchain systems. Despite their wide use, a
definition of this concept has not yet been distilled and formalized explicitly.
Instead, either the applications are proven directly based on the assumptions
underlying the function, or some property of the function is proven, but the security
of the application is argued only informally. The goal of this work is to provide
a (universal) definition that decouples the efforts of designing new moderately
hard functions and of building protocols based on them, serving as an interface
between the two. On a technical level, beyond the mentioned definitions, we instantiate
the model for four different notions of hardness. We extend the work of Alwen
and Serbinenko (STOC 2015) by providing a general tool for proving security for
the first notion of memory-hard functions that allows for provably secure applications.
The tool allows us to recover all of the graph-theoretic techniques developed
for proving security under the older, non-composable, notion of security used
by Alwen and Serbinenko. As an application of our definition of moderately hard
functions, we prove the security of two different schemes for proofs of effort
(PoE). We also formalize and instantiate the concept of a non-interactive proof
of effort (niPoE), in which the proof is not bound to a particular communication
context but rather any bit-string chosen by the prover.
alternative_title:
- LNCS
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Björn
full_name: Tackmann, Björn
last_name: Tackmann
citation:
ama: 'Alwen JF, Tackmann B. Moderately hard functions: Definition, instantiations,
and applications. In: Kalai Y, Reyzin L, eds. Vol 10677. Springer; 2017:493-526.
doi:10.1007/978-3-319-70500-2_17'
apa: 'Alwen, J. F., & Tackmann, B. (2017). Moderately hard functions: Definition,
instantiations, and applications. In Y. Kalai & L. Reyzin (Eds.) (Vol. 10677,
pp. 493–526). Presented at the TCC: Theory of Cryptography, Baltimore, MD, United
States: Springer. https://doi.org/10.1007/978-3-319-70500-2_17'
chicago: 'Alwen, Joel F, and Björn Tackmann. “Moderately Hard Functions: Definition,
Instantiations, and Applications.” edited by Yael Kalai and Leonid Reyzin, 10677:493–526.
Springer, 2017. https://doi.org/10.1007/978-3-319-70500-2_17.'
ieee: 'J. F. Alwen and B. Tackmann, “Moderately hard functions: Definition, instantiations,
and applications,” presented at the TCC: Theory of Cryptography, Baltimore, MD,
United States, 2017, vol. 10677, pp. 493–526.'
ista: 'Alwen JF, Tackmann B. 2017. Moderately hard functions: Definition, instantiations,
and applications. TCC: Theory of Cryptography, LNCS, vol. 10677, 493–526.'
mla: 'Alwen, Joel F., and Björn Tackmann. Moderately Hard Functions: Definition,
Instantiations, and Applications. Edited by Yael Kalai and Leonid Reyzin,
vol. 10677, Springer, 2017, pp. 493–526, doi:10.1007/978-3-319-70500-2_17.'
short: J.F. Alwen, B. Tackmann, in:, Y. Kalai, L. Reyzin (Eds.), Springer, 2017,
pp. 493–526.
conference:
end_date: 2017-11-15
location: Baltimore, MD, United States
name: 'TCC: Theory of Cryptography'
start_date: 2017-11-12
date_created: 2018-12-11T11:47:28Z
date_published: 2017-11-05T00:00:00Z
date_updated: 2021-01-12T08:06:04Z
day: '05'
department:
- _id: KrPi
doi: 10.1007/978-3-319-70500-2_17
editor:
- first_name: Yael
full_name: Kalai, Yael
last_name: Kalai
- first_name: Leonid
full_name: Reyzin, Leonid
last_name: Reyzin
intvolume: ' 10677'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2017/945
month: '11'
oa: 1
oa_version: Submitted Version
page: 493 - 526
publication_identifier:
isbn:
- 978-331970499-9
publication_status: published
publisher: Springer
publist_id: '7196'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'Moderately hard functions: Definition, instantiations, and applications'
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 10677
year: '2017'
...
---
_id: '635'
abstract:
- lang: eng
text: Memory-hard functions (MHFs) are hash algorithms whose evaluation cost is
dominated by memory cost. As memory, unlike computation, costs about the same
across different platforms, MHFs cannot be evaluated at significantly lower cost
on dedicated hardware like ASICs. MHFs have found widespread applications including
password hashing, key derivation, and proofs-of-work. This paper focuses on scrypt,
a simple candidate MHF designed by Percival, and described in RFC 7914. It has
been used within a number of cryptocurrencies (e.g., Litecoin and Dogecoin) and
has been an inspiration for Argon2d, one of the winners of the recent password-hashing
competition. Despite its popularity, no rigorous lower bounds on its memory complexity
are known. We prove that scrypt is optimally memory-hard, i.e., its cumulative
memory complexity (cmc) in the parallel random oracle model is Ω(n2w), where w
and n are the output length and number of invocations of the underlying hash function,
respectively. High cmc is a strong security target for MHFs introduced by Alwen
and Serbinenko (STOC’15) which implies high memory cost even for adversaries who
can amortize the cost over many evaluations and evaluate the underlying hash functions
many times in parallel. Our proof is the first showing optimal memory-hardness
for any MHF. Our result improves both quantitatively and qualitatively upon the
recent work by Alwen et al. (EUROCRYPT’16) who proved a weaker lower bound of
Ω(n2w/ log2 n) for a restricted class of adversaries.
alternative_title:
- LNCS
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Binchi
full_name: Chen, Binchi
last_name: Chen
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Leonid
full_name: Reyzin, Leonid
last_name: Reyzin
- first_name: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: 'Alwen JF, Chen B, Pietrzak KZ, Reyzin L, Tessaro S. Scrypt is maximally memory
hard. In: Coron J-S, Buus Nielsen J, eds. Vol 10212. Springer; 2017:33-62. doi:10.1007/978-3-319-56617-7_2'
apa: 'Alwen, J. F., Chen, B., Pietrzak, K. Z., Reyzin, L., & Tessaro, S. (2017).
Scrypt is maximally memory hard. In J.-S. Coron & J. Buus Nielsen (Eds.) (Vol.
10212, pp. 33–62). Presented at the EUROCRYPT: Theory and Applications of Cryptographic
Techniques, Paris, France: Springer. https://doi.org/10.1007/978-3-319-56617-7_2'
chicago: Alwen, Joel F, Binchi Chen, Krzysztof Z Pietrzak, Leonid Reyzin, and Stefano
Tessaro. “Scrypt Is Maximally Memory Hard.” edited by Jean-Sébastien Coron and
Jesper Buus Nielsen, 10212:33–62. Springer, 2017. https://doi.org/10.1007/978-3-319-56617-7_2.
ieee: 'J. F. Alwen, B. Chen, K. Z. Pietrzak, L. Reyzin, and S. Tessaro, “Scrypt
is maximally memory hard,” presented at the EUROCRYPT: Theory and Applications
of Cryptographic Techniques, Paris, France, 2017, vol. 10212, pp. 33–62.'
ista: 'Alwen JF, Chen B, Pietrzak KZ, Reyzin L, Tessaro S. 2017. Scrypt is maximally
memory hard. EUROCRYPT: Theory and Applications of Cryptographic Techniques, LNCS,
vol. 10212, 33–62.'
mla: Alwen, Joel F., et al. Scrypt Is Maximally Memory Hard. Edited by Jean-Sébastien
Coron and Jesper Buus Nielsen, vol. 10212, Springer, 2017, pp. 33–62, doi:10.1007/978-3-319-56617-7_2.
short: J.F. Alwen, B. Chen, K.Z. Pietrzak, L. Reyzin, S. Tessaro, in:, J.-S. Coron,
J. Buus Nielsen (Eds.), Springer, 2017, pp. 33–62.
conference:
end_date: 2017-05-04
location: Paris, France
name: 'EUROCRYPT: Theory and Applications of Cryptographic Techniques'
start_date: 2017-04-30
date_created: 2018-12-11T11:47:37Z
date_published: 2017-01-01T00:00:00Z
date_updated: 2021-01-12T08:07:10Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-319-56617-7_2
ec_funded: 1
editor:
- first_name: Jean-Sébastien
full_name: Coron, Jean-Sébastien
last_name: Coron
- first_name: Jesper
full_name: Buus Nielsen, Jesper
last_name: Buus Nielsen
intvolume: ' 10212'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/989
month: '01'
oa: 1
oa_version: Submitted Version
page: 33 - 62
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
isbn:
- 978-331956616-0
publication_status: published
publisher: Springer
publist_id: '7154'
quality_controlled: '1'
scopus_import: 1
status: public
title: Scrypt is maximally memory hard
type: conference
user_id: 4435EBFC-F248-11E8-B48F-1D18A9856A87
volume: 10212
year: '2017'
...
---
_id: '640'
abstract:
- lang: eng
text: 'Data-independent Memory Hard Functions (iMHFS) are finding a growing number
of applications in security; especially in the domain of password hashing. An
important property of a concrete iMHF is specified by fixing a directed acyclic
graph (DAG) Gn on n nodes. The quality of that iMHF is then captured by the following
two pebbling complexities of Gn: – The parallel cumulative pebbling complexity
Π∥cc(Gn) must be as high as possible (to ensure that the amortized cost of computing
the function on dedicated hardware is dominated by the cost of memory). – The
sequential space-time pebbling complexity Πst(Gn) should be as close as possible
to Π∥cc(Gn) (to ensure that using many cores in parallel and amortizing over many
instances does not give much of an advantage). In this paper we construct a family
of DAGs with best possible parameters in an asymptotic sense, i.e., where Π∥cc(Gn)
= Ω(n2/ log(n)) (which matches a known upper bound) and Πst(Gn) is within a constant
factor of Π∥cc(Gn). Our analysis relies on a new connection between the pebbling
complexity of a DAG and its depth-robustness (DR) – a well studied combinatorial
property. We show that high DR is sufficient for high Π∥cc. Alwen and Blocki (CRYPTO’16)
showed that high DR is necessary and so, together, these results fully characterize
DAGs with high Π∥cc in terms of DR. Complementing these results, we provide new
upper and lower bounds on the Π∥cc of several important candidate iMHFs from the
literature. We give the first lower bounds on the memory hardness of the Catena
and Balloon Hashing functions in a parallel model of computation and we give the
first lower bounds of any kind for (a version) of Argon2i. Finally we describe
a new class of pebbling attacks improving on those of Alwen and Blocki (CRYPTO’16).
By instantiating these attacks we upperbound the Π∥cc of the Password Hashing
Competition winner Argon2i and one of the Balloon Hashing functions by O (n1.71).
We also show an upper bound of O(n1.625) for the Catena functions and the two
remaining Balloon Hashing functions.'
alternative_title:
- LNCS
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Jeremiah
full_name: Blocki, Jeremiah
last_name: Blocki
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Alwen JF, Blocki J, Pietrzak KZ. Depth-robust graphs and their cumulative
memory complexity. In: Coron J-S, Buus Nielsen J, eds. Vol 10212. Springer; 2017:3-32.
doi:10.1007/978-3-319-56617-7_1'
apa: 'Alwen, J. F., Blocki, J., & Pietrzak, K. Z. (2017). Depth-robust graphs
and their cumulative memory complexity. In J.-S. Coron & J. Buus Nielsen (Eds.)
(Vol. 10212, pp. 3–32). Presented at the EUROCRYPT: Theory and Applications of
Cryptographic Techniques, Paris, France: Springer. https://doi.org/10.1007/978-3-319-56617-7_1'
chicago: Alwen, Joel F, Jeremiah Blocki, and Krzysztof Z Pietrzak. “Depth-Robust
Graphs and Their Cumulative Memory Complexity.” edited by Jean-Sébastien Coron
and Jesper Buus Nielsen, 10212:3–32. Springer, 2017. https://doi.org/10.1007/978-3-319-56617-7_1.
ieee: 'J. F. Alwen, J. Blocki, and K. Z. Pietrzak, “Depth-robust graphs and their
cumulative memory complexity,” presented at the EUROCRYPT: Theory and Applications
of Cryptographic Techniques, Paris, France, 2017, vol. 10212, pp. 3–32.'
ista: 'Alwen JF, Blocki J, Pietrzak KZ. 2017. Depth-robust graphs and their cumulative
memory complexity. EUROCRYPT: Theory and Applications of Cryptographic Techniques,
LNCS, vol. 10212, 3–32.'
mla: Alwen, Joel F., et al. Depth-Robust Graphs and Their Cumulative Memory Complexity.
Edited by Jean-Sébastien Coron and Jesper Buus Nielsen, vol. 10212, Springer,
2017, pp. 3–32, doi:10.1007/978-3-319-56617-7_1.
short: J.F. Alwen, J. Blocki, K.Z. Pietrzak, in:, J.-S. Coron, J. Buus Nielsen (Eds.),
Springer, 2017, pp. 3–32.
conference:
end_date: 2017-05-04
location: Paris, France
name: 'EUROCRYPT: Theory and Applications of Cryptographic Techniques'
start_date: 2017-04-30
date_created: 2018-12-11T11:47:39Z
date_published: 2017-04-01T00:00:00Z
date_updated: 2021-01-12T08:07:22Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-319-56617-7_1
ec_funded: 1
editor:
- first_name: Jean-Sébastien
full_name: Coron, Jean-Sébastien
last_name: Coron
- first_name: Jesper
full_name: Buus Nielsen, Jesper
last_name: Buus Nielsen
intvolume: ' 10212'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/875
month: '04'
oa: 1
oa_version: Submitted Version
page: 3 - 32
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
isbn:
- 978-331956616-0
publication_status: published
publisher: Springer
publist_id: '7148'
quality_controlled: '1'
scopus_import: 1
status: public
title: Depth-robust graphs and their cumulative memory complexity
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 10212
year: '2017'
...
---
_id: '648'
abstract:
- lang: eng
text: 'Pseudoentropy has found a lot of important applications to cryptography and
complexity theory. In this paper we focus on the foundational problem that has
not been investigated so far, namely by how much pseudoentropy (the amount seen
by computationally bounded attackers) differs from its information-theoretic counterpart
(seen by unbounded observers), given certain limits on attacker’s computational
power? We provide the following answer for HILL pseudoentropy, which exhibits
a threshold behavior around the size exponential in the entropy amount:– If the
attacker size (s) and advantage () satisfy s (formula presented) where k is the
claimed amount of pseudoentropy, then the pseudoentropy boils down to the information-theoretic
smooth entropy. – If s (formula presented) then pseudoentropy could be arbitrarily
bigger than the information-theoretic smooth entropy. Besides answering the posted
question, we show an elegant application of our result to the complexity theory,
namely that it implies the clas-sical result on the existence of functions hard
to approximate (due to Pippenger). In our approach we utilize non-constructive
techniques: the duality of linear programming and the probabilistic method.'
alternative_title:
- LNCS
author:
- first_name: Maciej
full_name: Skórski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skórski
citation:
ama: 'Skórski M. On the complexity of breaking pseudoentropy. In: Jäger G, Steila
S, eds. Vol 10185. Springer; 2017:600-613. doi:10.1007/978-3-319-55911-7_43'
apa: 'Skórski, M. (2017). On the complexity of breaking pseudoentropy. In G. Jäger
& S. Steila (Eds.) (Vol. 10185, pp. 600–613). Presented at the TAMC: Theory
and Applications of Models of Computation, Bern, Switzerland: Springer. https://doi.org/10.1007/978-3-319-55911-7_43'
chicago: Skórski, Maciej. “On the Complexity of Breaking Pseudoentropy.” edited
by Gerhard Jäger and Silvia Steila, 10185:600–613. Springer, 2017. https://doi.org/10.1007/978-3-319-55911-7_43.
ieee: 'M. Skórski, “On the complexity of breaking pseudoentropy,” presented at the
TAMC: Theory and Applications of Models of Computation, Bern, Switzerland, 2017,
vol. 10185, pp. 600–613.'
ista: 'Skórski M. 2017. On the complexity of breaking pseudoentropy. TAMC: Theory
and Applications of Models of Computation, LNCS, vol. 10185, 600–613.'
mla: Skórski, Maciej. On the Complexity of Breaking Pseudoentropy. Edited
by Gerhard Jäger and Silvia Steila, vol. 10185, Springer, 2017, pp. 600–13, doi:10.1007/978-3-319-55911-7_43.
short: M. Skórski, in:, G. Jäger, S. Steila (Eds.), Springer, 2017, pp. 600–613.
conference:
end_date: 2017-04-22
location: Bern, Switzerland
name: 'TAMC: Theory and Applications of Models of Computation'
start_date: 2017-04-20
date_created: 2018-12-11T11:47:42Z
date_published: 2017-04-01T00:00:00Z
date_updated: 2021-01-12T08:07:39Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-319-55911-7_43
editor:
- first_name: Gerhard
full_name: Jäger, Gerhard
last_name: Jäger
- first_name: Silvia
full_name: Steila, Silvia
last_name: Steila
intvolume: ' 10185'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/1186.pdf
month: '04'
oa: 1
oa_version: Submitted Version
page: 600 - 613
publication_identifier:
isbn:
- 978-331955910-0
publication_status: published
publisher: Springer
publist_id: '7125'
quality_controlled: '1'
scopus_import: 1
status: public
title: On the complexity of breaking pseudoentropy
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 10185
year: '2017'
...
---
_id: '650'
abstract:
- lang: eng
text: 'In this work we present a short and unified proof for the Strong and Weak
Regularity Lemma, based on the cryptographic tech-nique called low-complexity
approximations. In short, both problems reduce to a task of finding constructively
an approximation for a certain target function under a class of distinguishers
(test functions), where dis-tinguishers are combinations of simple rectangle-indicators.
In our case these approximations can be learned by a simple iterative procedure,
which yields a unified and simple proof, achieving for any graph with density
d and any approximation parameter the partition size. The novelty in our proof
is: (a) a simple approach which yields both strong and weaker variant, and (b)
improvements when d = o(1). At an abstract level, our proof can be seen a refinement
and simplification of the “analytic” proof given by Lovasz and Szegedy.'
alternative_title:
- LNCS
author:
- first_name: Maciej
full_name: Skórski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skórski
citation:
ama: 'Skórski M. A cryptographic view of regularity lemmas: Simpler unified proofs
and refined bounds. In: Jäger G, Steila S, eds. Vol 10185. Springer; 2017:586-599.
doi:10.1007/978-3-319-55911-7_42'
apa: 'Skórski, M. (2017). A cryptographic view of regularity lemmas: Simpler unified
proofs and refined bounds. In G. Jäger & S. Steila (Eds.) (Vol. 10185, pp.
586–599). Presented at the TAMC: Theory and Applications of Models of Computation,
Bern, Switzerland: Springer. https://doi.org/10.1007/978-3-319-55911-7_42'
chicago: 'Skórski, Maciej. “A Cryptographic View of Regularity Lemmas: Simpler Unified
Proofs and Refined Bounds.” edited by Gerhard Jäger and Silvia Steila, 10185:586–99.
Springer, 2017. https://doi.org/10.1007/978-3-319-55911-7_42.'
ieee: 'M. Skórski, “A cryptographic view of regularity lemmas: Simpler unified proofs
and refined bounds,” presented at the TAMC: Theory and Applications of Models
of Computation, Bern, Switzerland, 2017, vol. 10185, pp. 586–599.'
ista: 'Skórski M. 2017. A cryptographic view of regularity lemmas: Simpler unified
proofs and refined bounds. TAMC: Theory and Applications of Models of Computation,
LNCS, vol. 10185, 586–599.'
mla: 'Skórski, Maciej. A Cryptographic View of Regularity Lemmas: Simpler Unified
Proofs and Refined Bounds. Edited by Gerhard Jäger and Silvia Steila, vol.
10185, Springer, 2017, pp. 586–99, doi:10.1007/978-3-319-55911-7_42.'
short: M. Skórski, in:, G. Jäger, S. Steila (Eds.), Springer, 2017, pp. 586–599.
conference:
end_date: 2017-04-22
location: Bern, Switzerland
name: 'TAMC: Theory and Applications of Models of Computation'
start_date: 2017-04-20
date_created: 2018-12-11T11:47:42Z
date_published: 2017-01-01T00:00:00Z
date_updated: 2021-01-12T08:07:46Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-319-55911-7_42
editor:
- first_name: Gerhard
full_name: Jäger, Gerhard
last_name: Jäger
- first_name: Silvia
full_name: Steila, Silvia
last_name: Steila
intvolume: ' 10185'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/965.pdf
month: '01'
oa: 1
oa_version: Submitted Version
page: 586 - 599
publication_identifier:
issn:
- '03029743'
publication_status: published
publisher: Springer
publist_id: '7119'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'A cryptographic view of regularity lemmas: Simpler unified proofs and refined
bounds'
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 10185
year: '2017'
...
---
_id: '6527'
abstract:
- lang: eng
text: "A memory-hard function (MHF) ƒn with parameter n can be computed in sequential
time and space n. Simultaneously, a high amortized parallel area-time complexity
(aAT) is incurred per evaluation. In practice, MHFs are used to limit the rate
at which an adversary (using a custom computational device) can evaluate a security
sensitive function that still occasionally needs to be evaluated by honest users
(using an off-the-shelf general purpose device). The most prevalent examples of
such sensitive functions are Key Derivation Functions (KDFs) and password hashing
algorithms where rate limits help mitigate off-line dictionary attacks. As the
honest users' inputs to these functions are often (low-entropy) passwords special
attention is given to a class of side-channel resistant MHFs called iMHFs.\r\n\r\nEssentially
all iMHFs can be viewed as some mode of operation (making n calls to some round
function) given by a directed acyclic graph (DAG) with very low indegree. Recently,
a combinatorial property of a DAG has been identified (called \"depth-robustness\")
which results in good provable security for an iMHF based on that DAG. Depth-robust
DAGs have also proven useful in other cryptographic applications. Unfortunately,
up till now, all known very depth-robust DAGs are impractically complicated and
little is known about their exact (i.e. non-asymptotic) depth-robustness both
in theory and in practice.\r\n\r\nIn this work we build and analyze (both formally
and empirically) several exceedingly simple and efficient to navigate practical
DAGs for use in iMHFs and other applications. For each DAG we:\r\n*Prove that
their depth-robustness is asymptotically maximal.\r\n*Prove bounds of at least
3 orders of magnitude better on their exact depth-robustness compared to known
bounds for other practical iMHF.\r\n*Implement and empirically evaluate their
depth-robustness and aAT against a variety of state-of-the art (and several new)
depth-reduction and low aAT attacks. \r\nWe find that, against all attacks, the
new DAGs perform significantly better in practice than Argon2i, the most widely
deployed iMHF in practice.\r\n\r\nAlong the way we also improve the best known
empirical attacks on the aAT of Argon2i by implementing and testing several heuristic
versions of a (hitherto purely theoretical) depth-reduction attack. Finally, we
demonstrate practicality of our constructions by modifying the Argon2i code base
to use one of the new high aAT DAGs. Experimental benchmarks on a standard off-the-shelf
CPU show that the new modifications do not adversely affect the impressive throughput
of Argon2i (despite seemingly enjoying significantly higher aAT).\r\n"
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Jeremiah
full_name: Blocki, Jeremiah
last_name: Blocki
- first_name: Ben
full_name: Harsha, Ben
last_name: Harsha
citation:
ama: 'Alwen JF, Blocki J, Harsha B. Practical graphs for optimal side-channel resistant
memory-hard functions. In: Proceedings of the 2017 ACM SIGSAC Conference on
Computer and Communications Security. ACM Press; 2017:1001-1017. doi:10.1145/3133956.3134031'
apa: 'Alwen, J. F., Blocki, J., & Harsha, B. (2017). Practical graphs for optimal
side-channel resistant memory-hard functions. In Proceedings of the 2017 ACM
SIGSAC Conference on Computer and Communications Security (pp. 1001–1017).
Dallas, TX, USA: ACM Press. https://doi.org/10.1145/3133956.3134031'
chicago: Alwen, Joel F, Jeremiah Blocki, and Ben Harsha. “Practical Graphs for Optimal
Side-Channel Resistant Memory-Hard Functions.” In Proceedings of the 2017 ACM
SIGSAC Conference on Computer and Communications Security, 1001–17. ACM Press,
2017. https://doi.org/10.1145/3133956.3134031.
ieee: J. F. Alwen, J. Blocki, and B. Harsha, “Practical graphs for optimal side-channel
resistant memory-hard functions,” in Proceedings of the 2017 ACM SIGSAC Conference
on Computer and Communications Security, Dallas, TX, USA, 2017, pp. 1001–1017.
ista: 'Alwen JF, Blocki J, Harsha B. 2017. Practical graphs for optimal side-channel
resistant memory-hard functions. Proceedings of the 2017 ACM SIGSAC Conference
on Computer and Communications Security. CCS: Conference on Computer and Communications
Security, 1001–1017.'
mla: Alwen, Joel F., et al. “Practical Graphs for Optimal Side-Channel Resistant
Memory-Hard Functions.” Proceedings of the 2017 ACM SIGSAC Conference on Computer
and Communications Security, ACM Press, 2017, pp. 1001–17, doi:10.1145/3133956.3134031.
short: J.F. Alwen, J. Blocki, B. Harsha, in:, Proceedings of the 2017 ACM SIGSAC
Conference on Computer and Communications Security, ACM Press, 2017, pp. 1001–1017.
conference:
end_date: 2017-11-03
location: Dallas, TX, USA
name: 'CCS: Conference on Computer and Communications Security'
start_date: 2017-10-30
date_created: 2019-06-06T13:21:29Z
date_published: 2017-10-30T00:00:00Z
date_updated: 2021-01-12T08:07:53Z
day: '30'
department:
- _id: KrPi
doi: 10.1145/3133956.3134031
ec_funded: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2017/443
month: '10'
oa: 1
oa_version: Submitted Version
page: 1001-1017
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication: Proceedings of the 2017 ACM SIGSAC Conference on Computer and Communications
Security
publication_identifier:
isbn:
- '9781450349468'
publication_status: published
publisher: ACM Press
quality_controlled: '1'
scopus_import: 1
status: public
title: Practical graphs for optimal side-channel resistant memory-hard functions
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2017'
...
---
_id: '6526'
abstract:
- lang: eng
text: 'This paper studies the complexity of estimating Rényi divergences of discrete
distributions: p observed from samples and the baseline distribution q known a
priori. Extending the results of Acharya et al. (SODA''15) on estimating Rényi
entropy, we present improved estimation techniques together with upper and lower
bounds on the sample complexity. We show that, contrarily to estimating Rényi
entropy where a sublinear (in the alphabet size) number of samples suffices, the
sample complexity is heavily dependent on events occurring unlikely in q, and
is unbounded in general (no matter what an estimation technique is used). For
any divergence of integer order bigger than 1, we provide upper and lower bounds
on the number of samples dependent on probabilities of p and q (the lower bounds
hold for non-integer orders as well). We conclude that the worst-case sample complexity
is polynomial in the alphabet size if and only if the probabilities of q are non-negligible.
This gives theoretical insights into heuristics used in the applied literature
to handle numerical instability, which occurs for small probabilities of q. Our
result shows that they should be handled with care not only because of numerical
issues, but also because of a blow up in the sample complexity.'
article_number: '8006529'
author:
- first_name: Maciej
full_name: Skórski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skórski
citation:
ama: 'Skórski M. On the complexity of estimating Rènyi divergences. In: 2017
IEEE International Symposium on Information Theory (ISIT). IEEE; 2017. doi:10.1109/isit.2017.8006529'
apa: 'Skórski, M. (2017). On the complexity of estimating Rènyi divergences. In
2017 IEEE International Symposium on Information Theory (ISIT). Aachen,
Germany: IEEE. https://doi.org/10.1109/isit.2017.8006529'
chicago: Skórski, Maciej. “On the Complexity of Estimating Rènyi Divergences.” In
2017 IEEE International Symposium on Information Theory (ISIT). IEEE, 2017.
https://doi.org/10.1109/isit.2017.8006529.
ieee: M. Skórski, “On the complexity of estimating Rènyi divergences,” in 2017
IEEE International Symposium on Information Theory (ISIT), Aachen, Germany,
2017.
ista: 'Skórski M. 2017. On the complexity of estimating Rènyi divergences. 2017
IEEE International Symposium on Information Theory (ISIT). ISIT: International
Symposium on Information Theory, 8006529.'
mla: Skórski, Maciej. “On the Complexity of Estimating Rènyi Divergences.” 2017
IEEE International Symposium on Information Theory (ISIT), 8006529, IEEE,
2017, doi:10.1109/isit.2017.8006529.
short: M. Skórski, in:, 2017 IEEE International Symposium on Information Theory
(ISIT), IEEE, 2017.
conference:
end_date: 2017-06-30
location: Aachen, Germany
name: 'ISIT: International Symposium on Information Theory'
start_date: 2017-06-25
date_created: 2019-06-06T12:53:09Z
date_published: 2017-08-09T00:00:00Z
date_updated: 2021-01-12T08:07:53Z
day: '09'
department:
- _id: KrPi
doi: 10.1109/isit.2017.8006529
ec_funded: 1
external_id:
arxiv:
- '1702.01666'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1702.01666
month: '08'
oa: 1
oa_version: Preprint
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication: 2017 IEEE International Symposium on Information Theory (ISIT)
publication_identifier:
isbn:
- '9781509040964'
publication_status: published
publisher: IEEE
quality_controlled: '1'
scopus_import: 1
status: public
title: On the complexity of estimating Rènyi divergences
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
year: '2017'
...
---
_id: '697'
abstract:
- lang: eng
text: 'De, Trevisan and Tulsiani [CRYPTO 2010] show that every distribution over
n-bit strings which has constant statistical distance to uniform (e.g., the output
of a pseudorandom generator mapping n-1 to n bit strings), can be distinguished
from the uniform distribution with advantage epsilon by a circuit of size O( 2^n
epsilon^2). We generalize this result, showing that a distribution which has less
than k bits of min-entropy, can be distinguished from any distribution with k
bits of delta-smooth min-entropy with advantage epsilon by a circuit of size O(2^k
epsilon^2/delta^2). As a special case, this implies that any distribution with
support at most 2^k (e.g., the output of a pseudoentropy generator mapping k to
n bit strings) can be distinguished from any given distribution with min-entropy
k+1 with advantage epsilon by a circuit of size O(2^k epsilon^2). Our result thus
shows that pseudoentropy distributions face basically the same non-uniform attacks
as pseudorandom distributions. '
alternative_title:
- LIPIcs
article_number: '39'
author:
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Maciej
full_name: Skórski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skórski
citation:
ama: 'Pietrzak KZ, Skórski M. Non uniform attacks against pseudoentropy. In: Vol
80. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2017. doi:10.4230/LIPIcs.ICALP.2017.39'
apa: 'Pietrzak, K. Z., & Skórski, M. (2017). Non uniform attacks against pseudoentropy
(Vol. 80). Presented at the ICALP: International Colloquium on Automata, Languages,
and Programming, Warsaw, Poland: Schloss Dagstuhl - Leibniz-Zentrum für Informatik.
https://doi.org/10.4230/LIPIcs.ICALP.2017.39'
chicago: Pietrzak, Krzysztof Z, and Maciej Skórski. “Non Uniform Attacks against
Pseudoentropy,” Vol. 80. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017.
https://doi.org/10.4230/LIPIcs.ICALP.2017.39.
ieee: 'K. Z. Pietrzak and M. Skórski, “Non uniform attacks against pseudoentropy,”
presented at the ICALP: International Colloquium on Automata, Languages, and Programming,
Warsaw, Poland, 2017, vol. 80.'
ista: 'Pietrzak KZ, Skórski M. 2017. Non uniform attacks against pseudoentropy.
ICALP: International Colloquium on Automata, Languages, and Programming, LIPIcs,
vol. 80, 39.'
mla: Pietrzak, Krzysztof Z., and Maciej Skórski. Non Uniform Attacks against
Pseudoentropy. Vol. 80, 39, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
2017, doi:10.4230/LIPIcs.ICALP.2017.39.
short: K.Z. Pietrzak, M. Skórski, in:, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
2017.
conference:
end_date: 2017-07-14
location: Warsaw, Poland
name: 'ICALP: International Colloquium on Automata, Languages, and Programming'
start_date: 2017-07-10
date_created: 2018-12-11T11:47:59Z
date_published: 2017-07-01T00:00:00Z
date_updated: 2021-01-12T08:11:15Z
day: '01'
ddc:
- '005'
department:
- _id: KrPi
doi: 10.4230/LIPIcs.ICALP.2017.39
ec_funded: 1
file:
- access_level: open_access
checksum: e95618a001692f1af2d68f5fde43bc1f
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:08:40Z
date_updated: 2020-07-14T12:47:46Z
file_id: '4701'
file_name: IST-2017-893-v1+1_LIPIcs-ICALP-2017-39.pdf
file_size: 601004
relation: main_file
file_date_updated: 2020-07-14T12:47:46Z
has_accepted_license: '1'
intvolume: ' 80'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
issn:
- '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
publist_id: '7003'
pubrep_id: '893'
quality_controlled: '1'
scopus_import: 1
status: public
title: Non uniform attacks against pseudoentropy
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 80
year: '2017'
...
---
_id: '710'
abstract:
- lang: eng
text: 'We revisit the problem of estimating entropy of discrete distributions from
independent samples, studied recently by Acharya, Orlitsky, Suresh and Tyagi (SODA
2015), improving their upper and lower bounds on the necessary sample size n.
For estimating Renyi entropy of order alpha, up to constant accuracy and error
probability, we show the following * Upper bounds n = O(1) 2^{(1-1/alpha)H_alpha}
for integer alpha>1, as the worst case over distributions with Renyi entropy
equal to H_alpha. * Lower bounds n = Omega(1) K^{1-1/alpha} for any real alpha>1,
with the constant being an inverse polynomial of the accuracy, as the worst case
over all distributions on K elements. Our upper bounds essentially replace the
alphabet size by a factor exponential in the entropy, which offers improvements
especially in low or medium entropy regimes (interesting for example in anomaly
detection). As for the lower bounds, our proof explicitly shows how the complexity
depends on both alphabet and accuracy, partially solving the open problem posted
in previous works. The argument for upper bounds derives a clean identity for
the variance of falling-power sum of a multinomial distribution. Our approach
for lower bounds utilizes convex optimization to find a distribution with possibly
worse estimation performance, and may be of independent interest as a tool to
work with Le Cam’s two point method. '
alternative_title:
- LIPIcs
article_number: '20'
author:
- first_name: Maciej
full_name: Obremski, Maciej
last_name: Obremski
- first_name: Maciej
full_name: Skórski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skórski
citation:
ama: 'Obremski M, Skórski M. Renyi entropy estimation revisited. In: Vol 81. Schloss
Dagstuhl - Leibniz-Zentrum für Informatik; 2017. doi:10.4230/LIPIcs.APPROX-RANDOM.2017.20'
apa: 'Obremski, M., & Skórski, M. (2017). Renyi entropy estimation revisited
(Vol. 81). Presented at the 20th International Workshop on Approximation Algorithms
for Combinatorial Optimization Problems, APPROX, Berkeley, USA: Schloss Dagstuhl
- Leibniz-Zentrum für Informatik. https://doi.org/10.4230/LIPIcs.APPROX-RANDOM.2017.20'
chicago: Obremski, Maciej, and Maciej Skórski. “Renyi Entropy Estimation Revisited,”
Vol. 81. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017. https://doi.org/10.4230/LIPIcs.APPROX-RANDOM.2017.20.
ieee: M. Obremski and M. Skórski, “Renyi entropy estimation revisited,” presented
at the 20th International Workshop on Approximation Algorithms for Combinatorial
Optimization Problems, APPROX, Berkeley, USA, 2017, vol. 81.
ista: Obremski M, Skórski M. 2017. Renyi entropy estimation revisited. 20th International
Workshop on Approximation Algorithms for Combinatorial Optimization Problems,
APPROX, LIPIcs, vol. 81, 20.
mla: Obremski, Maciej, and Maciej Skórski. Renyi Entropy Estimation Revisited.
Vol. 81, 20, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017, doi:10.4230/LIPIcs.APPROX-RANDOM.2017.20.
short: M. Obremski, M. Skórski, in:, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
2017.
conference:
end_date: 2017-08-18
location: Berkeley, USA
name: 20th International Workshop on Approximation Algorithms for Combinatorial
Optimization Problems, APPROX
start_date: 2017-08-18
date_created: 2018-12-11T11:48:04Z
date_published: 2017-08-01T00:00:00Z
date_updated: 2021-01-12T08:11:50Z
day: '01'
ddc:
- '005'
- '600'
department:
- _id: KrPi
doi: 10.4230/LIPIcs.APPROX-RANDOM.2017.20
ec_funded: 1
file:
- access_level: open_access
checksum: 89225c7dcec2c93838458c9102858985
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:13:10Z
date_updated: 2020-07-14T12:47:49Z
file_id: '4991'
file_name: IST-2017-888-v1+1_LIPIcs-APPROX-RANDOM-2017-20.pdf
file_size: 604813
relation: main_file
file_date_updated: 2020-07-14T12:47:49Z
has_accepted_license: '1'
intvolume: ' 81'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
issn:
- '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
publist_id: '6979'
pubrep_id: '888'
quality_controlled: '1'
scopus_import: 1
status: public
title: Renyi entropy estimation revisited
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 81
year: '2017'
...
---
_id: '838'
abstract:
- lang: eng
text: 'In this thesis we discuss the exact security of message authentications codes
HMAC , NMAC , and PMAC . NMAC is a mode of operation which turns a fixed input-length
keyed hash function f into a variable input-length function. A practical single-key
variant of NMAC called HMAC is a very popular and widely deployed message authentication
code (MAC). PMAC is a block-cipher based mode of operation, which also happens
to be the most famous fully parallel MAC. NMAC was introduced by Bellare, Canetti
and Krawczyk Crypto’96, who proved it to be a secure pseudorandom function (PRF),
and thus also a MAC, under two assumptions. Unfortunately, for many instantiations
of HMAC one of them has been found to be wrong. To restore the provable guarantees
for NMAC , Bellare [Crypto’06] showed its security without this assumption. PMAC
was introduced by Black and Rogaway at Eurocrypt 2002. If instantiated with a
pseudorandom permutation over n -bit strings, PMAC constitutes a provably secure
variable input-length PRF. For adversaries making q queries, each of length at
most ` (in n -bit blocks), and of total length σ ≤ q` , the original paper proves
an upper bound on the distinguishing advantage of O ( σ 2 / 2 n ), while the currently
best bound is O ( qσ/ 2 n ). In this work we show that this bound is tight by
giving an attack with advantage Ω( q 2 `/ 2 n ). In the PMAC construction one
initially XORs a mask to every message block, where the mask for the i th block
is computed as τ i := γ i · L , where L is a (secret) random value, and γ i is
the i -th codeword of the Gray code. Our attack applies more generally to any
sequence of γ i ’s which contains a large coset of a subgroup of GF (2 n ). As
for NMAC , our first contribution is a simpler and uniform proof: If f is an ε
-secure PRF (against q queries) and a δ - non-adaptively secure PRF (against q
queries), then NMAC f is an ( ε + `qδ )-secure PRF against q queries of length
at most ` blocks each. We also show that this ε + `qδ bound is basically tight
by constructing an f for which an attack with advantage `qδ exists. Moreover,
we analyze the PRF-security of a modification of NMAC called NI by An and Bellare
that avoids the constant rekeying on multi-block messages in NMAC and allows for
an information-theoretic analysis. We carry out such an analysis, obtaining a
tight `q 2 / 2 c bound for this step, improving over the trivial bound of ` 2
q 2 / 2 c . Finally, we investigate, if the security of PMAC can be further improved
by using τ i ’s that are k -wise independent, for k > 1 (the original has k
= 1). We observe that the security of PMAC will not increase in general if k =
2, and then prove that the security increases to O ( q 2 / 2 n ), if the k = 4.
Due to simple extension attacks, this is the best bound one can hope for, using
any distribution on the masks. Whether k = 3 is already sufficient to get this
level of security is left as an open problem. Keywords: Message authentication
codes, Pseudorandom functions, HMAC, PMAC. '
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Michal
full_name: Rybar, Michal
id: 2B3E3DE8-F248-11E8-B48F-1D18A9856A87
last_name: Rybar
citation:
ama: Rybar M. (The exact security of) Message authentication codes. 2017. doi:10.15479/AT:ISTA:th_828
apa: Rybar, M. (2017). (The exact security of) Message authentication codes.
Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_828
chicago: Rybar, Michal. “(The Exact Security of) Message Authentication Codes.”
Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_828.
ieee: M. Rybar, “(The exact security of) Message authentication codes,” Institute
of Science and Technology Austria, 2017.
ista: Rybar M. 2017. (The exact security of) Message authentication codes. Institute
of Science and Technology Austria.
mla: Rybar, Michal. (The Exact Security of) Message Authentication Codes.
Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_828.
short: M. Rybar, (The Exact Security of) Message Authentication Codes, Institute
of Science and Technology Austria, 2017.
date_created: 2018-12-11T11:48:46Z
date_published: 2017-06-26T00:00:00Z
date_updated: 2023-09-07T12:02:28Z
day: '26'
ddc:
- '000'
degree_awarded: PhD
department:
- _id: KrPi
doi: 10.15479/AT:ISTA:th_828
file:
- access_level: open_access
checksum: ff8639ec4bded6186f44c7bd3ee26804
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:10:13Z
date_updated: 2020-07-14T12:48:12Z
file_id: '4799'
file_name: IST-2017-828-v1+3_2017_Rybar_thesis.pdf
file_size: 847400
relation: main_file
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checksum: 3462101745ce8ad199c2d0f75dae4a7e
content_type: application/zip
creator: dernst
date_created: 2019-04-05T08:24:11Z
date_updated: 2020-07-14T12:48:12Z
file_id: '6202'
file_name: 2017_Thesis_Rybar_source.zip
file_size: 26054879
relation: source_file
file_date_updated: 2020-07-14T12:48:12Z
has_accepted_license: '1'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
page: '86'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
publist_id: '6810'
pubrep_id: '828'
related_material:
record:
- id: '2082'
relation: part_of_dissertation
status: public
- id: '6196'
relation: part_of_dissertation
status: public
status: public
title: (The exact security of) Message authentication codes
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2017'
...
---
_id: '6196'
abstract:
- lang: eng
text: PMAC is a simple and parallel block-cipher mode of operation, which was introduced
by Black and Rogaway at Eurocrypt 2002. If instantiated with a (pseudo)random
permutation over n-bit strings, PMAC constitutes a provably secure variable input-length
(pseudo)random function. For adversaries making q queries, each of length at most
l (in n-bit blocks), and of total length σ ≤ ql, the original paper proves an
upper bound on the distinguishing advantage of Ο(σ2/2n), while the currently
best bound is Ο (qσ/2n).In this work we show that this bound is tight by giving
an attack with advantage Ω (q2l/2n). In the PMAC construction one initially XORs
a mask to every message block, where the mask for the ith block is computed as
τi := γi·L, where L is a (secret) random value, and γi is the i-th codeword of
the Gray code. Our attack applies more generally to any sequence of γi’s which
contains a large coset of a subgroup of GF(2n). We then investigate if the security
of PMAC can be further improved by using τi’s that are k-wise independent, for
k > 1 (the original distribution is only 1-wise independent). We observe that
the security of PMAC will not increase in general, even if the masks are chosen
from a 2-wise independent distribution, and then prove that the security increases
to O(q<2/2n), if the τi are 4-wise independent. Due to simple extension attacks,
this is the best bound one can hope for, using any distribution on the masks.
Whether 3-wise independence is already sufficient to get this level of security
is left as an open problem.
author:
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Michal
full_name: Rybar, Michal
id: 2B3E3DE8-F248-11E8-B48F-1D18A9856A87
last_name: Rybar
citation:
ama: Gazi P, Pietrzak KZ, Rybar M. The exact security of PMAC. IACR Transactions
on Symmetric Cryptology. 2017;2016(2):145-161. doi:10.13154/TOSC.V2016.I2.145-161
apa: Gazi, P., Pietrzak, K. Z., & Rybar, M. (2017). The exact security of PMAC.
IACR Transactions on Symmetric Cryptology. Ruhr University Bochum. https://doi.org/10.13154/TOSC.V2016.I2.145-161
chicago: Gazi, Peter, Krzysztof Z Pietrzak, and Michal Rybar. “The Exact Security
of PMAC.” IACR Transactions on Symmetric Cryptology. Ruhr University Bochum,
2017. https://doi.org/10.13154/TOSC.V2016.I2.145-161.
ieee: P. Gazi, K. Z. Pietrzak, and M. Rybar, “The exact security of PMAC,” IACR
Transactions on Symmetric Cryptology, vol. 2016, no. 2. Ruhr University Bochum,
pp. 145–161, 2017.
ista: Gazi P, Pietrzak KZ, Rybar M. 2017. The exact security of PMAC. IACR Transactions
on Symmetric Cryptology. 2016(2), 145–161.
mla: Gazi, Peter, et al. “The Exact Security of PMAC.” IACR Transactions on Symmetric
Cryptology, vol. 2016, no. 2, Ruhr University Bochum, 2017, pp. 145–61, doi:10.13154/TOSC.V2016.I2.145-161.
short: P. Gazi, K.Z. Pietrzak, M. Rybar, IACR Transactions on Symmetric Cryptology
2016 (2017) 145–161.
date_created: 2019-04-04T13:48:23Z
date_published: 2017-02-03T00:00:00Z
date_updated: 2023-09-07T12:02:27Z
day: '03'
ddc:
- '000'
department:
- _id: KrPi
doi: 10.13154/TOSC.V2016.I2.145-161
ec_funded: 1
file:
- access_level: open_access
checksum: f23161d685dd957ae8d7274132999684
content_type: application/pdf
creator: dernst
date_created: 2019-04-04T13:53:58Z
date_updated: 2020-07-14T12:47:24Z
file_id: '6197'
file_name: 2017_IACR_Gazi.pdf
file_size: 597335
relation: main_file
file_date_updated: 2020-07-14T12:47:24Z
has_accepted_license: '1'
intvolume: ' 2016'
issue: '2'
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
page: 145-161
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication: IACR Transactions on Symmetric Cryptology
publication_identifier:
eissn:
- 2519-173X
publication_status: published
publisher: Ruhr University Bochum
quality_controlled: '1'
related_material:
record:
- id: '838'
relation: dissertation_contains
status: public
status: public
title: The exact security of PMAC
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 2016
year: '2017'
...
---
_id: '559'
abstract:
- lang: eng
text: 'Proofs of space (PoS) were suggested as more ecological and economical alternative
to proofs of work, which are currently used in blockchain designs like Bitcoin.
The existing PoS are based on rather sophisticated graph pebbling lower bounds.
Much simpler and in several aspects more efficient schemes based on inverting
random functions have been suggested, but they don’t give meaningful security
guarantees due to existing time-memory trade-offs. In particular, Hellman showed
that any permutation over a domain of size N can be inverted in time T by an algorithm
that is given S bits of auxiliary information whenever (Formula presented). For
functions Hellman gives a weaker attack with S2· T≈ N2 (e.g., S= T≈ N2/3). To
prove lower bounds, one considers an adversary who has access to an oracle f:
[ N] → [N] and can make T oracle queries. The best known lower bound is S· T∈
Ω(N) and holds for random functions and permutations. We construct functions that
provably require more time and/or space to invert. Specifically, for any constant
k we construct a function [N] → [N] that cannot be inverted unless Sk· T∈ Ω(Nk)
(in particular, S= T≈ (Formula presented). Our construction does not contradict
Hellman’s time-memory trade-off, because it cannot be efficiently evaluated in
forward direction. However, its entire function table can be computed in time
quasilinear in N, which is sufficient for the PoS application. Our simplest construction
is built from a random function oracle g: [N] × [N] → [ N] and a random permutation
oracle f: [N] → N] and is defined as h(x) = g(x, x′) where f(x) = π(f(x′)) with
π being any involution without a fixed point, e.g. flipping all the bits. For
this function we prove that any adversary who gets S bits of auxiliary information,
makes at most T oracle queries, and inverts h on an ϵ fraction of outputs must
satisfy S2· T∈ Ω(ϵ2N2).'
alternative_title:
- LNCS
author:
- first_name: Hamza M
full_name: Abusalah, Hamza M
id: 40297222-F248-11E8-B48F-1D18A9856A87
last_name: Abusalah
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Bram
full_name: Cohen, Bram
last_name: Cohen
- first_name: Danylo
full_name: Khilko, Danylo
last_name: Khilko
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Leonid
full_name: Reyzin, Leonid
last_name: Reyzin
citation:
ama: 'Abusalah HM, Alwen JF, Cohen B, Khilko D, Pietrzak KZ, Reyzin L. Beyond Hellman’s
time-memory trade-offs with applications to proofs of space. In: Vol 10625. Springer;
2017:357-379. doi:10.1007/978-3-319-70697-9_13'
apa: 'Abusalah, H. M., Alwen, J. F., Cohen, B., Khilko, D., Pietrzak, K. Z., &
Reyzin, L. (2017). Beyond Hellman’s time-memory trade-offs with applications to
proofs of space (Vol. 10625, pp. 357–379). Presented at the ASIACRYPT: Theory
and Applications of Cryptology and Information Security, Hong Kong, China: Springer.
https://doi.org/10.1007/978-3-319-70697-9_13'
chicago: Abusalah, Hamza M, Joel F Alwen, Bram Cohen, Danylo Khilko, Krzysztof Z
Pietrzak, and Leonid Reyzin. “Beyond Hellman’s Time-Memory Trade-Offs with Applications
to Proofs of Space,” 10625:357–79. Springer, 2017. https://doi.org/10.1007/978-3-319-70697-9_13.
ieee: 'H. M. Abusalah, J. F. Alwen, B. Cohen, D. Khilko, K. Z. Pietrzak, and L.
Reyzin, “Beyond Hellman’s time-memory trade-offs with applications to proofs of
space,” presented at the ASIACRYPT: Theory and Applications of Cryptology and
Information Security, Hong Kong, China, 2017, vol. 10625, pp. 357–379.'
ista: 'Abusalah HM, Alwen JF, Cohen B, Khilko D, Pietrzak KZ, Reyzin L. 2017. Beyond
Hellman’s time-memory trade-offs with applications to proofs of space. ASIACRYPT:
Theory and Applications of Cryptology and Information Security, LNCS, vol. 10625,
357–379.'
mla: Abusalah, Hamza M., et al. Beyond Hellman’s Time-Memory Trade-Offs with
Applications to Proofs of Space. Vol. 10625, Springer, 2017, pp. 357–79, doi:10.1007/978-3-319-70697-9_13.
short: H.M. Abusalah, J.F. Alwen, B. Cohen, D. Khilko, K.Z. Pietrzak, L. Reyzin,
in:, Springer, 2017, pp. 357–379.
conference:
end_date: 2017-12-07
location: Hong Kong, China
name: 'ASIACRYPT: Theory and Applications of Cryptology and Information Security'
start_date: 2017-12-03
date_created: 2018-12-11T11:47:10Z
date_published: 2017-11-18T00:00:00Z
date_updated: 2023-09-07T12:30:22Z
day: '18'
department:
- _id: KrPi
doi: 10.1007/978-3-319-70697-9_13
ec_funded: 1
intvolume: ' 10625'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2017/893.pdf
month: '11'
oa: 1
oa_version: Submitted Version
page: 357 - 379
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
isbn:
- 978-331970696-2
publication_status: published
publisher: Springer
publist_id: '7257'
quality_controlled: '1'
related_material:
record:
- id: '83'
relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Beyond Hellman’s time-memory trade-offs with applications to proofs of space
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 10625
year: '2017'
...
---
_id: '637'
abstract:
- lang: eng
text: For many cryptographic primitives, it is relatively easy to achieve selective
security (where the adversary commits a-priori to some of the choices to be made
later in the attack) but appears difficult to achieve the more natural notion
of adaptive security (where the adversary can make all choices on the go as the
attack progresses). A series of several recent works shows how to cleverly achieve
adaptive security in several such scenarios including generalized selective decryption
(Panjwani, TCC ’07 and Fuchsbauer et al., CRYPTO ’15), constrained PRFs (Fuchsbauer
et al., ASIACRYPT ’14), and Yao garbled circuits (Jafargholi and Wichs, TCC ’16b).
Although the above works expressed vague intuition that they share a common technique,
the connection was never made precise. In this work we present a new framework
that connects all of these works and allows us to present them in a unified and
simplified fashion. Moreover, we use the framework to derive a new result for
adaptively secure secret sharing over access structures defined via monotone circuits.
We envision that further applications will follow in the future. Underlying our
framework is the following simple idea. It is well known that selective security,
where the adversary commits to n-bits of information about his future choices,
automatically implies adaptive security at the cost of amplifying the adversary’s
advantage by a factor of up to 2n. However, in some cases the proof of selective
security proceeds via a sequence of hybrids, where each pair of adjacent hybrids
locally only requires some smaller partial information consisting of m ≪ n bits.
The partial information needed might be completely different between different
pairs of hybrids, and if we look across all the hybrids we might rely on the entire
n-bit commitment. Nevertheless, the above is sufficient to prove adaptive security,
at the cost of amplifying the adversary’s advantage by a factor of only 2m ≪ 2n.
In all of our examples using the above framework, the different hybrids are captured
by some sort of a graph pebbling game and the amount of information that the adversary
needs to commit to in each pair of hybrids is bounded by the maximum number of
pebbles in play at any point in time. Therefore, coming up with better strategies
for proving adaptive security translates to various pebbling strategies for different
types of graphs.
alternative_title:
- LNCS
author:
- first_name: Zahra
full_name: Jafargholi, Zahra
last_name: Jafargholi
- first_name: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
- first_name: Karen
full_name: Klein, Karen
id: 3E83A2F8-F248-11E8-B48F-1D18A9856A87
last_name: Klein
- first_name: Ilan
full_name: Komargodski, Ilan
last_name: Komargodski
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Daniel
full_name: Wichs, Daniel
last_name: Wichs
citation:
ama: 'Jafargholi Z, Kamath Hosdurg C, Klein K, Komargodski I, Pietrzak KZ, Wichs
D. Be adaptive avoid overcommitting. In: Katz J, Shacham H, eds. Vol 10401. Springer;
2017:133-163. doi:10.1007/978-3-319-63688-7_5'
apa: 'Jafargholi, Z., Kamath Hosdurg, C., Klein, K., Komargodski, I., Pietrzak,
K. Z., & Wichs, D. (2017). Be adaptive avoid overcommitting. In J. Katz &
H. Shacham (Eds.) (Vol. 10401, pp. 133–163). Presented at the CRYPTO: Cryptology,
Santa Barbara, CA, United States: Springer. https://doi.org/10.1007/978-3-319-63688-7_5'
chicago: Jafargholi, Zahra, Chethan Kamath Hosdurg, Karen Klein, Ilan Komargodski,
Krzysztof Z Pietrzak, and Daniel Wichs. “Be Adaptive Avoid Overcommitting.” edited
by Jonathan Katz and Hovav Shacham, 10401:133–63. Springer, 2017. https://doi.org/10.1007/978-3-319-63688-7_5.
ieee: 'Z. Jafargholi, C. Kamath Hosdurg, K. Klein, I. Komargodski, K. Z. Pietrzak,
and D. Wichs, “Be adaptive avoid overcommitting,” presented at the CRYPTO: Cryptology,
Santa Barbara, CA, United States, 2017, vol. 10401, pp. 133–163.'
ista: 'Jafargholi Z, Kamath Hosdurg C, Klein K, Komargodski I, Pietrzak KZ, Wichs
D. 2017. Be adaptive avoid overcommitting. CRYPTO: Cryptology, LNCS, vol. 10401,
133–163.'
mla: Jafargholi, Zahra, et al. Be Adaptive Avoid Overcommitting. Edited by
Jonathan Katz and Hovav Shacham, vol. 10401, Springer, 2017, pp. 133–63, doi:10.1007/978-3-319-63688-7_5.
short: Z. Jafargholi, C. Kamath Hosdurg, K. Klein, I. Komargodski, K.Z. Pietrzak,
D. Wichs, in:, J. Katz, H. Shacham (Eds.), Springer, 2017, pp. 133–163.
conference:
end_date: 2017-07-24
location: Santa Barbara, CA, United States
name: 'CRYPTO: Cryptology'
start_date: 2017-07-20
date_created: 2018-12-11T11:47:38Z
date_published: 2017-01-01T00:00:00Z
date_updated: 2023-09-07T13:32:11Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-319-63688-7_5
ec_funded: 1
editor:
- first_name: Jonathan
full_name: Katz, Jonathan
last_name: Katz
- first_name: Hovav
full_name: Shacham, Hovav
last_name: Shacham
intvolume: ' 10401'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2017/515
month: '01'
oa: 1
oa_version: Submitted Version
page: 133 - 163
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
isbn:
- 978-331963687-0
publication_status: published
publisher: Springer
publist_id: '7151'
quality_controlled: '1'
related_material:
record:
- id: '10035'
relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Be adaptive avoid overcommitting
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 10401
year: '2017'
...
---
_id: '1174'
abstract:
- lang: eng
text: Security of cryptographic applications is typically defined by security games.
The adversary, within certain resources, cannot win with probability much better
than 0 (for unpredictability applications, like one-way functions) or much better
than 1/2 (indistinguishability applications for instance encryption schemes).
In so called squared-friendly applications the winning probability of the adversary,
for different values of the application secret randomness, is not only close to
0 or 1/2 on average, but also concentrated in the sense that its second central
moment is small. The class of squared-friendly applications, which contains all
unpredictability applications and many indistinguishability applications, is particularly
important for key derivation. Barak et al. observed that for square-friendly applications
one can beat the "RT-bound", extracting secure keys with significantly
smaller entropy loss. In turn Dodis and Yu showed that in squared-friendly applications
one can directly use a "weak" key, which has only high entropy, as a
secure key. In this paper we give sharp lower bounds on square security assuming
security for "weak" keys. We show that any application which is either
(a) secure with weak keys or (b) allows for entropy savings for keys derived by
universal hashing, must be square-friendly. Quantitatively, our lower bounds match
the positive results of Dodis and Yu and Barak et al. (TCC\'13, CRYPTO\'11) Hence,
they can be understood as a general characterization of squared-friendly applications.
While the positive results on squared-friendly applications where derived by one
clever application of the Cauchy-Schwarz Inequality, for tight lower bounds we
need more machinery. In our approach we use convex optimization techniques and
some theory of circular matrices.
alternative_title:
- LIPIcs
article_number: '57'
article_processing_charge: No
author:
- first_name: Maciej
full_name: Skórski, Maciej
id: EC09FA6A-02D0-11E9-8223-86B7C91467DD
last_name: Skórski
citation:
ama: 'Skórski M. Lower bounds on key derivation for square-friendly applications.
In: Vol 66. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2017. doi:10.4230/LIPIcs.STACS.2017.57'
apa: 'Skórski, M. (2017). Lower bounds on key derivation for square-friendly applications
(Vol. 66). Presented at the STACS: Symposium on Theoretical Aspects of Computer
Science, Hannover, Germany: Schloss Dagstuhl - Leibniz-Zentrum für Informatik.
https://doi.org/10.4230/LIPIcs.STACS.2017.57'
chicago: Skórski, Maciej. “Lower Bounds on Key Derivation for Square-Friendly Applications,”
Vol. 66. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017. https://doi.org/10.4230/LIPIcs.STACS.2017.57.
ieee: 'M. Skórski, “Lower bounds on key derivation for square-friendly applications,”
presented at the STACS: Symposium on Theoretical Aspects of Computer Science,
Hannover, Germany, 2017, vol. 66.'
ista: 'Skórski M. 2017. Lower bounds on key derivation for square-friendly applications.
STACS: Symposium on Theoretical Aspects of Computer Science, LIPIcs, vol. 66,
57.'
mla: Skórski, Maciej. Lower Bounds on Key Derivation for Square-Friendly Applications.
Vol. 66, 57, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017, doi:10.4230/LIPIcs.STACS.2017.57.
short: M. Skórski, in:, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2017.
conference:
end_date: 2017-03-11
location: Hannover, Germany
name: 'STACS: Symposium on Theoretical Aspects of Computer Science'
start_date: 2017-03-08
date_created: 2018-12-11T11:50:32Z
date_published: 2017-03-01T00:00:00Z
date_updated: 2023-09-20T11:23:15Z
day: '01'
department:
- _id: KrPi
doi: 10.4230/LIPIcs.STACS.2017.57
ec_funded: 1
external_id:
isi:
- '000521077300057'
intvolume: ' 66'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://drops.dagstuhl.de/opus/volltexte/2017/6976
month: '03'
oa: 1
oa_version: Submitted Version
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_identifier:
issn:
- '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
publist_id: '6180'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Lower bounds on key derivation for square-friendly applications
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 66
year: '2017'
...
---
_id: '1176'
abstract:
- lang: eng
text: The algorithm Argon2i-B of Biryukov, Dinu and Khovratovich is currently being
considered by the IRTF (Internet Research Task Force) as a new de-facto standard
for password hashing. An older version (Argon2i-A) of the same algorithm was chosen
as the winner of the recent Password Hashing Competition. An important competitor
to Argon2i-B is the recently introduced Balloon Hashing (BH) algorithm of Corrigan-Gibs,
Boneh and Schechter. A key security desiderata for any such algorithm is that
evaluating it (even using a custom device) requires a large amount of memory amortized
across multiple instances. Alwen and Blocki (CRYPTO 2016) introduced a class of
theoretical attacks against Argon2i-A and BH. While these attacks yield large
asymptotic reductions in the amount of memory, it was not, a priori, clear if
(1) they can be extended to the newer Argon2i-B, (2) the attacks are effective
on any algorithm for practical parameter ranges (e.g., 1GB of memory) and (3)
if they can be effectively instantiated against any algorithm under realistic
hardware constrains. In this work we answer all three of these questions in the
affirmative for all three algorithms. This is also the first work to analyze the
security of Argon2i-B. In more detail, we extend the theoretical attacks of Alwen
and Blocki (CRYPTO 2016) to the recent Argon2i-B proposal demonstrating severe
asymptotic deficiencies in its security. Next we introduce several novel heuristics
for improving the attack's concrete memory efficiency even when on-chip memory
bandwidth is bounded. We then simulate our attacks on randomly sampled Argon2i-A,
Argon2i-B and BH instances and measure the resulting memory consumption for various
practical parameter ranges and for a variety of upperbounds on the amount of parallelism
available to the attacker. Finally we describe, implement, and test a new heuristic
for applying the Alwen-Blocki attack to functions employing a technique developed
by Corrigan-Gibs et al. for improving concrete security of memory-hard functions.
We analyze the collected data and show the effects various parameters have on
the memory consumption of the attack. In particular, we can draw several interesting
conclusions about the level of security provided by these functions. · For the
Alwen-Blocki attack to fail against practical memory parameters, Argon2i-B must
be instantiated with more than 10 passes on memory - beyond the "paranoid" parameter
setting in the current IRTF proposal. · The technique of Corrigan-Gibs for improving
security can also be overcome by the Alwen-Blocki attack under realistic hardware
constraints. · On a positive note, both the asymptotic and concrete security of
Argon2i-B seem to improve on that of Argon2i-A.
article_number: '7961977'
article_processing_charge: No
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Jeremiah
full_name: Blocki, Jeremiah
last_name: Blocki
citation:
ama: 'Alwen JF, Blocki J. Towards practical attacks on Argon2i and balloon hashing.
In: IEEE; 2017. doi:10.1109/EuroSP.2017.47'
apa: 'Alwen, J. F., & Blocki, J. (2017). Towards practical attacks on Argon2i
and balloon hashing. Presented at the EuroS&P: European Symposium on Security
and Privacy, Paris, France: IEEE. https://doi.org/10.1109/EuroSP.2017.47'
chicago: Alwen, Joel F, and Jeremiah Blocki. “Towards Practical Attacks on Argon2i
and Balloon Hashing.” IEEE, 2017. https://doi.org/10.1109/EuroSP.2017.47.
ieee: 'J. F. Alwen and J. Blocki, “Towards practical attacks on Argon2i and balloon
hashing,” presented at the EuroS&P: European Symposium on Security and Privacy,
Paris, France, 2017.'
ista: 'Alwen JF, Blocki J. 2017. Towards practical attacks on Argon2i and balloon
hashing. EuroS&P: European Symposium on Security and Privacy, 7961977.'
mla: Alwen, Joel F., and Jeremiah Blocki. Towards Practical Attacks on Argon2i
and Balloon Hashing. 7961977, IEEE, 2017, doi:10.1109/EuroSP.2017.47.
short: J.F. Alwen, J. Blocki, in:, IEEE, 2017.
conference:
end_date: 2017-04-28
location: Paris, France
name: 'EuroS&P: European Symposium on Security and Privacy'
start_date: 2017-04-26
date_created: 2018-12-11T11:50:33Z
date_published: 2017-07-03T00:00:00Z
date_updated: 2023-09-20T11:22:25Z
day: '03'
department:
- _id: KrPi
doi: 10.1109/EuroSP.2017.47
external_id:
isi:
- '000424197300011'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/759
month: '07'
oa: 1
oa_version: Submitted Version
publication_identifier:
isbn:
- 978-150905761-0
publication_status: published
publisher: IEEE
publist_id: '6178'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Towards practical attacks on Argon2i and balloon hashing
type: conference
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2017'
...
---
_id: '1187'
abstract:
- lang: eng
text: We construct efficient authentication protocols and message authentication
codes (MACs) whose security can be reduced to the learning parity with noise (LPN)
problem. Despite a large body of work—starting with the (Formula presented.) protocol
of Hopper and Blum in 2001—until now it was not even known how to construct an
efficient authentication protocol from LPN which is secure against man-in-the-middle
attacks. A MAC implies such a (two-round) protocol.
article_processing_charge: No
article_type: original
author:
- first_name: Eike
full_name: Kiltz, Eike
last_name: Kiltz
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Daniele
full_name: Venturi, Daniele
last_name: Venturi
- first_name: David
full_name: Cash, David
last_name: Cash
- first_name: Abhishek
full_name: Jain, Abhishek
last_name: Jain
citation:
ama: Kiltz E, Pietrzak KZ, Venturi D, Cash D, Jain A. Efficient authentication from
hard learning problems. Journal of Cryptology. 2017;30(4):1238-1275. doi:10.1007/s00145-016-9247-3
apa: Kiltz, E., Pietrzak, K. Z., Venturi, D., Cash, D., & Jain, A. (2017). Efficient
authentication from hard learning problems. Journal of Cryptology. Springer.
https://doi.org/10.1007/s00145-016-9247-3
chicago: Kiltz, Eike, Krzysztof Z Pietrzak, Daniele Venturi, David Cash, and Abhishek
Jain. “Efficient Authentication from Hard Learning Problems.” Journal of Cryptology.
Springer, 2017. https://doi.org/10.1007/s00145-016-9247-3.
ieee: E. Kiltz, K. Z. Pietrzak, D. Venturi, D. Cash, and A. Jain, “Efficient authentication
from hard learning problems,” Journal of Cryptology, vol. 30, no. 4. Springer,
pp. 1238–1275, 2017.
ista: Kiltz E, Pietrzak KZ, Venturi D, Cash D, Jain A. 2017. Efficient authentication
from hard learning problems. Journal of Cryptology. 30(4), 1238–1275.
mla: Kiltz, Eike, et al. “Efficient Authentication from Hard Learning Problems.”
Journal of Cryptology, vol. 30, no. 4, Springer, 2017, pp. 1238–75, doi:10.1007/s00145-016-9247-3.
short: E. Kiltz, K.Z. Pietrzak, D. Venturi, D. Cash, A. Jain, Journal of Cryptology
30 (2017) 1238–1275.
date_created: 2018-12-11T11:50:37Z
date_published: 2017-10-01T00:00:00Z
date_updated: 2023-09-20T11:20:58Z
day: '01'
ddc:
- '000'
department:
- _id: KrPi
doi: 10.1007/s00145-016-9247-3
ec_funded: 1
external_id:
isi:
- '000410788600007'
file:
- access_level: open_access
checksum: c647520d115b772a1682fc06fa273eb1
content_type: application/pdf
creator: dernst
date_created: 2020-05-14T16:30:17Z
date_updated: 2020-07-14T12:44:37Z
file_id: '7843'
file_name: 2017_JournalCrypto_Kiltz.pdf
file_size: 516959
relation: main_file
file_date_updated: 2020-07-14T12:44:37Z
has_accepted_license: '1'
intvolume: ' 30'
isi: 1
issue: '4'
language:
- iso: eng
month: '10'
oa: 1
oa_version: Submitted Version
page: 1238 - 1275
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: Journal of Cryptology
publication_status: published
publisher: Springer
publist_id: '6166'
quality_controlled: '1'
related_material:
record:
- id: '3238'
relation: earlier_version
status: public
scopus_import: '1'
status: public
title: Efficient authentication from hard learning problems
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 30
year: '2017'
...
---
_id: '1177'
abstract:
- lang: eng
text: Boldyreva, Palacio and Warinschi introduced a multiple forking game as an
extension of general forking. The notion of (multiple) forking is a useful abstraction
from the actual simulation of cryptographic scheme to the adversary in a security
reduction, and is achieved through the intermediary of a so-called wrapper algorithm.
Multiple forking has turned out to be a useful tool in the security argument of
several cryptographic protocols. However, a reduction employing multiple forking
incurs a significant degradation of (Formula presented.) , where (Formula presented.)
denotes the upper bound on the underlying random oracle calls and (Formula presented.)
, the number of forkings. In this work we take a closer look at the reasons for
the degradation with a tighter security bound in mind. We nail down the exact
set of conditions for success in the multiple forking game. A careful analysis
of the cryptographic schemes and corresponding security reduction employing multiple
forking leads to the formulation of ‘dependence’ and ‘independence’ conditions
pertaining to the output of the wrapper in different rounds. Based on the (in)dependence
conditions we propose a general framework of multiple forking and a General Multiple
Forking Lemma. Leveraging (in)dependence to the full allows us to improve the
degradation factor in the multiple forking game by a factor of (Formula presented.).
By implication, the cost of a single forking involving two random oracles (augmented
forking) matches that involving a single random oracle (elementary forking). Finally,
we study the effect of these observations on the concrete security of existing
schemes employing multiple forking. We conclude that by careful design of the
protocol (and the wrapper in the security reduction) it is possible to harness
our observations to the full extent.
acknowledgement: "We are grateful to the anonymous reviewers for their insightful
comments. The\r\ndetailed reports helped us a lot to address the technical mistakes
as well as to improve the overall presentation of the paper."
author:
- first_name: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
- first_name: Sanjit
full_name: Chatterjee, Sanjit
last_name: Chatterjee
citation:
ama: 'Kamath Hosdurg C, Chatterjee S. A closer look at multiple-forking: Leveraging
(in)dependence for a tighter bound. Algorithmica. 2016;74(4):1321-1362.
doi:10.1007/s00453-015-9997-6'
apa: 'Kamath Hosdurg, C., & Chatterjee, S. (2016). A closer look at multiple-forking:
Leveraging (in)dependence for a tighter bound. Algorithmica. Springer.
https://doi.org/10.1007/s00453-015-9997-6'
chicago: 'Kamath Hosdurg, Chethan, and Sanjit Chatterjee. “A Closer Look at Multiple-Forking:
Leveraging (in)Dependence for a Tighter Bound.” Algorithmica. Springer,
2016. https://doi.org/10.1007/s00453-015-9997-6.'
ieee: 'C. Kamath Hosdurg and S. Chatterjee, “A closer look at multiple-forking:
Leveraging (in)dependence for a tighter bound,” Algorithmica, vol. 74,
no. 4. Springer, pp. 1321–1362, 2016.'
ista: 'Kamath Hosdurg C, Chatterjee S. 2016. A closer look at multiple-forking:
Leveraging (in)dependence for a tighter bound. Algorithmica. 74(4), 1321–1362.'
mla: 'Kamath Hosdurg, Chethan, and Sanjit Chatterjee. “A Closer Look at Multiple-Forking:
Leveraging (in)Dependence for a Tighter Bound.” Algorithmica, vol. 74,
no. 4, Springer, 2016, pp. 1321–62, doi:10.1007/s00453-015-9997-6.'
short: C. Kamath Hosdurg, S. Chatterjee, Algorithmica 74 (2016) 1321–1362.
date_created: 2018-12-11T11:50:33Z
date_published: 2016-04-01T00:00:00Z
date_updated: 2021-01-12T06:48:52Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/s00453-015-9997-6
intvolume: ' 74'
issue: '4'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://eprint.iacr.org/2013/651
month: '04'
oa: 1
oa_version: Submitted Version
page: 1321 - 1362
publication: Algorithmica
publication_status: published
publisher: Springer
publist_id: '6177'
quality_controlled: '1'
status: public
title: 'A closer look at multiple-forking: Leveraging (in)dependence for a tighter
bound'
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 74
year: '2016'
...
---
_id: '1179'
abstract:
- lang: eng
text: "Computational notions of entropy have recently found many applications, including
leakage-resilient cryptography, deterministic encryption or memory delegation.
The two main types of results which make computational notions so useful are (1)
Chain rules, which quantify by how much the computational entropy of a variable
decreases if conditioned on some other variable (2) Transformations, which quantify
to which extend one type of entropy implies another.\r\n\r\nSuch chain rules and
transformations typically lose a significant amount in quality of the entropy,
and are the reason why applying these results one gets rather weak quantitative
security bounds. In this paper we for the first time prove lower bounds in this
context, showing that existing results for transformations are, unfortunately,
basically optimal for non-adaptive black-box reductions (and it’s hard to imagine
how non black-box reductions or adaptivity could be useful here.)\r\n\r\nA variable
X has k bits of HILL entropy of quality (ϵ,s)\r\nif there exists a variable Y
with k bits min-entropy which cannot be distinguished from X with advantage ϵ\r\n\r\nby
distinguishing circuits of size s. A weaker notion is Metric entropy, where we
switch quantifiers, and only require that for every distinguisher of size s, such
a Y exists.\r\n\r\nWe first describe our result concerning transformations. By
definition, HILL implies Metric without any loss in quality. Metric entropy often
comes up in applications, but must be transformed to HILL for meaningful security
guarantees. The best known result states that if a variable X has k bits of Metric
entropy of quality (ϵ,s)\r\n, then it has k bits of HILL with quality (2ϵ,s⋅ϵ2).
We show that this loss of a factor Ω(ϵ−2)\r\n\r\nin circuit size is necessary.
In fact, we show the stronger result that this loss is already necessary when
transforming so called deterministic real valued Metric entropy to randomised
boolean Metric (both these variants of Metric entropy are implied by HILL without
loss in quality).\r\n\r\nThe chain rule for HILL entropy states that if X has
k bits of HILL entropy of quality (ϵ,s)\r\n, then for any variable Z of length
m, X conditioned on Z has k−m bits of HILL entropy with quality (ϵ,s⋅ϵ2/2m). We
show that a loss of Ω(2m/ϵ) in circuit size necessary here. Note that this still
leaves a gap of ϵ between the known bound and our lower bound."
acknowledgement: "K. Pietrzak—Supported by the European Research Council consolidator
grant (682815-TOCNeT).\r\nM. Skórski—Supported by the National Science Center, Poland
(2015/17/N/ST6/03564)."
alternative_title:
- LNCS
author:
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Skorski
full_name: Maciej, Skorski
last_name: Maciej
citation:
ama: 'Pietrzak KZ, Maciej S. Pseudoentropy: Lower-bounds for chain rules and transformations.
In: Vol 9985. Springer; 2016:183-203. doi:10.1007/978-3-662-53641-4_8'
apa: 'Pietrzak, K. Z., & Maciej, S. (2016). Pseudoentropy: Lower-bounds for
chain rules and transformations (Vol. 9985, pp. 183–203). Presented at the TCC:
Theory of Cryptography Conference, Beijing, China: Springer. https://doi.org/10.1007/978-3-662-53641-4_8'
chicago: 'Pietrzak, Krzysztof Z, and Skorski Maciej. “Pseudoentropy: Lower-Bounds
for Chain Rules and Transformations,” 9985:183–203. Springer, 2016. https://doi.org/10.1007/978-3-662-53641-4_8.'
ieee: 'K. Z. Pietrzak and S. Maciej, “Pseudoentropy: Lower-bounds for chain rules
and transformations,” presented at the TCC: Theory of Cryptography Conference,
Beijing, China, 2016, vol. 9985, pp. 183–203.'
ista: 'Pietrzak KZ, Maciej S. 2016. Pseudoentropy: Lower-bounds for chain rules
and transformations. TCC: Theory of Cryptography Conference, LNCS, vol. 9985,
183–203.'
mla: 'Pietrzak, Krzysztof Z., and Skorski Maciej. Pseudoentropy: Lower-Bounds
for Chain Rules and Transformations. Vol. 9985, Springer, 2016, pp. 183–203,
doi:10.1007/978-3-662-53641-4_8.'
short: K.Z. Pietrzak, S. Maciej, in:, Springer, 2016, pp. 183–203.
conference:
end_date: 2016-11-03
location: Beijing, China
name: 'TCC: Theory of Cryptography Conference'
start_date: 2016-10-31
date_created: 2018-12-11T11:50:34Z
date_published: 2016-10-22T00:00:00Z
date_updated: 2021-01-12T06:48:53Z
day: '22'
department:
- _id: KrPi
doi: 10.1007/978-3-662-53641-4_8
ec_funded: 1
intvolume: ' 9985'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/159
month: '10'
oa: 1
oa_version: Preprint
page: 183 - 203
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_status: published
publisher: Springer
publist_id: '6175'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'Pseudoentropy: Lower-bounds for chain rules and transformations'
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 9985
year: '2016'
...
---
_id: '1231'
abstract:
- lang: eng
text: 'We study the time-and memory-complexities of the problem of computing labels
of (multiple) randomly selected challenge-nodes in a directed acyclic graph. The
w-bit label of a node is the hash of the labels of its parents, and the hash function
is modeled as a random oracle. Specific instances of this problem underlie both
proofs of space [Dziembowski et al. CRYPTO’15] as well as popular memory-hard
functions like scrypt. As our main tool, we introduce the new notion of a probabilistic
parallel entangled pebbling game, a new type of combinatorial pebbling game on
a graph, which is closely related to the labeling game on the same graph. As a
first application of our framework, we prove that for scrypt, when the underlying
hash function is invoked n times, the cumulative memory complexity (CMC) (a notion
recently introduced by Alwen and Serbinenko (STOC’15) to capture amortized memory-hardness
for parallel adversaries) is at least Ω(w · (n/ log(n))2). This bound holds for
adversaries that can store many natural functions of the labels (e.g., linear
combinations), but still not arbitrary functions thereof. We then introduce and
study a combinatorial quantity, and show how a sufficiently small upper bound
on it (which we conjecture) extends our CMC bound for scrypt to hold against arbitrary
adversaries. We also show that such an upper bound solves the main open problem
for proofs-of-space protocols: namely, establishing that the time complexity of
computing the label of a random node in a graph on n nodes (given an initial kw-bit
state) reduces tightly to the time complexity for black pebbling on the same graph
(given an initial k-node pebbling).'
acknowledgement: "Joël Alwen, Chethan Kamath, and Krzysztof Pietrzak’s research is
partially supported by an ERC starting grant (259668-PSPC). Vladimir Kolmogorov
is partially supported by an ERC consolidator grant (616160-DOICV). Binyi Chen was
partially supported by NSF grants CNS-1423566 and CNS-1514526, and a gift from the
Gareatis Foundation. Stefano Tessaro was partially supported by NSF grants CNS-1423566,
CNS-1528178, a Hellman Fellowship, and the Glen and Susanne Culler Chair.\r\n\r\nThis
work was done in part while the authors were visiting the Simons Institute for the
Theory of Computing, supported by the Simons Foundation and by the DIMACS/Simons
Collaboration in Cryptography through NSF grant CNS-1523467."
alternative_title:
- LNCS
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Binyi
full_name: Chen, Binyi
last_name: Chen
- first_name: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
- first_name: Vladimir
full_name: Kolmogorov, Vladimir
id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87
last_name: Kolmogorov
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: 'Alwen JF, Chen B, Kamath Hosdurg C, Kolmogorov V, Pietrzak KZ, Tessaro S.
On the complexity of scrypt and proofs of space in the parallel random oracle
model. In: Vol 9666. Springer; 2016:358-387. doi:10.1007/978-3-662-49896-5_13'
apa: 'Alwen, J. F., Chen, B., Kamath Hosdurg, C., Kolmogorov, V., Pietrzak, K. Z.,
& Tessaro, S. (2016). On the complexity of scrypt and proofs of space in the
parallel random oracle model (Vol. 9666, pp. 358–387). Presented at the EUROCRYPT:
Theory and Applications of Cryptographic Techniques, Vienna, Austria: Springer.
https://doi.org/10.1007/978-3-662-49896-5_13'
chicago: Alwen, Joel F, Binyi Chen, Chethan Kamath Hosdurg, Vladimir Kolmogorov,
Krzysztof Z Pietrzak, and Stefano Tessaro. “On the Complexity of Scrypt and Proofs
of Space in the Parallel Random Oracle Model,” 9666:358–87. Springer, 2016. https://doi.org/10.1007/978-3-662-49896-5_13.
ieee: 'J. F. Alwen, B. Chen, C. Kamath Hosdurg, V. Kolmogorov, K. Z. Pietrzak, and
S. Tessaro, “On the complexity of scrypt and proofs of space in the parallel random
oracle model,” presented at the EUROCRYPT: Theory and Applications of Cryptographic
Techniques, Vienna, Austria, 2016, vol. 9666, pp. 358–387.'
ista: 'Alwen JF, Chen B, Kamath Hosdurg C, Kolmogorov V, Pietrzak KZ, Tessaro S.
2016. On the complexity of scrypt and proofs of space in the parallel random oracle
model. EUROCRYPT: Theory and Applications of Cryptographic Techniques, LNCS, vol.
9666, 358–387.'
mla: Alwen, Joel F., et al. On the Complexity of Scrypt and Proofs of Space in
the Parallel Random Oracle Model. Vol. 9666, Springer, 2016, pp. 358–87, doi:10.1007/978-3-662-49896-5_13.
short: J.F. Alwen, B. Chen, C. Kamath Hosdurg, V. Kolmogorov, K.Z. Pietrzak, S.
Tessaro, in:, Springer, 2016, pp. 358–387.
conference:
end_date: 2016-05-12
location: Vienna, Austria
name: 'EUROCRYPT: Theory and Applications of Cryptographic Techniques'
start_date: 2016-05-08
date_created: 2018-12-11T11:50:51Z
date_published: 2016-04-28T00:00:00Z
date_updated: 2021-01-12T06:49:15Z
day: '28'
department:
- _id: KrPi
- _id: VlKo
doi: 10.1007/978-3-662-49896-5_13
ec_funded: 1
intvolume: ' 9666'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/100
month: '04'
oa: 1
oa_version: Submitted Version
page: 358 - 387
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
- _id: 25FBA906-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '616160'
name: 'Discrete Optimization in Computer Vision: Theory and Practice'
publication_status: published
publisher: Springer
publist_id: '6103'
quality_controlled: '1'
scopus_import: 1
status: public
title: On the complexity of scrypt and proofs of space in the parallel random oracle
model
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 9666
year: '2016'
...
---
_id: '1233'
abstract:
- lang: eng
text: About three decades ago it was realized that implementing private channels
between parties which can be adaptively corrupted requires an encryption scheme
that is secure against selective opening attacks. Whether standard (IND-CPA) security
implies security against selective opening attacks has been a major open question
since. The only known reduction from selective opening to IND-CPA security loses
an exponential factor. A polynomial reduction is only known for the very special
case where the distribution considered in the selective opening security experiment
is a product distribution, i.e., the messages are sampled independently from each
other. In this paper we give a reduction whose loss is quantified via the dependence
graph (where message dependencies correspond to edges) of the underlying message
distribution. In particular, for some concrete distributions including Markov
distributions, our reduction is polynomial.
acknowledgement: G. Fuchsbauer and K. Pietrzak are supported by the European Research
Council, ERC Starting Grant (259668-PSPC). F. Heuer is funded by a Sofja Kovalevskaja
Award of the Alexander von Humboldt Foundation and DFG SPP 1736, Algorithms for
BIG DATA. E. Kiltz is supported by a Sofja Kovalevskaja Award of the Alexander von
Humboldt Foundation, the German Israel Foundation, and ERC Project ERCC (FP7/615074).
alternative_title:
- LNCS
author:
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Felix
full_name: Heuer, Felix
last_name: Heuer
- first_name: Eike
full_name: Kiltz, Eike
last_name: Kiltz
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Fuchsbauer G, Heuer F, Kiltz E, Pietrzak KZ. Standard security does imply
security against selective opening for markov distributions. In: Vol 9562. Springer;
2016:282-305. doi:10.1007/978-3-662-49096-9_12'
apa: 'Fuchsbauer, G., Heuer, F., Kiltz, E., & Pietrzak, K. Z. (2016). Standard
security does imply security against selective opening for markov distributions
(Vol. 9562, pp. 282–305). Presented at the TCC: Theory of Cryptography Conference,
Tel Aviv, Israel: Springer. https://doi.org/10.1007/978-3-662-49096-9_12'
chicago: Fuchsbauer, Georg, Felix Heuer, Eike Kiltz, and Krzysztof Z Pietrzak. “Standard
Security Does Imply Security against Selective Opening for Markov Distributions,”
9562:282–305. Springer, 2016. https://doi.org/10.1007/978-3-662-49096-9_12.
ieee: 'G. Fuchsbauer, F. Heuer, E. Kiltz, and K. Z. Pietrzak, “Standard security
does imply security against selective opening for markov distributions,” presented
at the TCC: Theory of Cryptography Conference, Tel Aviv, Israel, 2016, vol. 9562,
pp. 282–305.'
ista: 'Fuchsbauer G, Heuer F, Kiltz E, Pietrzak KZ. 2016. Standard security does
imply security against selective opening for markov distributions. TCC: Theory
of Cryptography Conference, LNCS, vol. 9562, 282–305.'
mla: Fuchsbauer, Georg, et al. Standard Security Does Imply Security against
Selective Opening for Markov Distributions. Vol. 9562, Springer, 2016, pp.
282–305, doi:10.1007/978-3-662-49096-9_12.
short: G. Fuchsbauer, F. Heuer, E. Kiltz, K.Z. Pietrzak, in:, Springer, 2016, pp.
282–305.
conference:
end_date: 2016-01-13
location: Tel Aviv, Israel
name: 'TCC: Theory of Cryptography Conference'
start_date: 2016-01-10
date_created: 2018-12-11T11:50:51Z
date_published: 2016-01-01T00:00:00Z
date_updated: 2021-01-12T06:49:16Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-662-49096-9_12
ec_funded: 1
intvolume: ' 9562'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2015/853
month: '01'
oa: 1
oa_version: Submitted Version
page: 282 - 305
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '6100'
quality_controlled: '1'
scopus_import: 1
status: public
title: Standard security does imply security against selective opening for markov
distributions
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 9562
year: '2016'
...
---
_id: '1365'
abstract:
- lang: eng
text: A memory-hard function (MHF) f is equipped with a space cost σ and time cost
τ parameter such that repeatedly computing fσ,τ on an application specific integrated
circuit (ASIC) is not economically advantageous relative to a general purpose
computer. Technically we would like that any (generalized) circuit for evaluating
an iMHF fσ,τ has area × time (AT) complexity at Θ(σ2 ∗ τ). A data-independent
MHF (iMHF) has the added property that it can be computed with almost optimal
memory and time complexity by an algorithm which accesses memory in a pattern
independent of the input value. Such functions can be specified by fixing a directed
acyclic graph (DAG) G on n = Θ(σ ∗ τ) nodes representing its computation graph.
In this work we develop new tools for analyzing iMHFs. First we define and motivate
a new complexity measure capturing the amount of energy (i.e. electricity) required
to compute a function. We argue that, in practice, this measure is at least as
important as the more traditional AT-complexity. Next we describe an algorithm
A for repeatedly evaluating an iMHF based on an arbitrary DAG G. We upperbound
both its energy and AT complexities per instance evaluated in terms of a certain
combinatorial property of G. Next we instantiate our attack for several general
classes of DAGs which include those underlying many of the most important iMHF
candidates in the literature. In particular, we obtain the following results which
hold for all choices of parameters σ and τ (and thread-count) such that n = σ
∗ τ. -The Catena-Dragonfly function of [FLW13] has AT and energy complexities
O(n1.67). -The Catena-Butterfly function of [FLW13] has complexities is O(n1.67).
-The Double-Buffer and the Linear functions of [CGBS16] both have complexities
in O(n1.67). -The Argon2i function of [BDK15] (winner of the Password Hashing
Competition [PHC]) has complexities O(n7/4 log(n)). -The Single-Buffer function
of [CGBS16] has complexities O(n7/4 log(n)). -Any iMHF can be computed by an algorithm
with complexities O(n2/ log1 −ε(n)) for all ε > 0. In particular when τ = 1
this shows that the goal of constructing an iMHF with AT-complexity Θ(σ2 ∗ τ )
is unachievable. Along the way we prove a lemma upper-bounding the depth-robustness
of any DAG which may prove to be of independent interest.
alternative_title:
- LNCS
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Jeremiah
full_name: Blocki, Jeremiah
last_name: Blocki
citation:
ama: 'Alwen JF, Blocki J. Efficiently computing data-independent memory-hard functions.
In: Vol 9815. Springer; 2016:241-271. doi:10.1007/978-3-662-53008-5_9'
apa: 'Alwen, J. F., & Blocki, J. (2016). Efficiently computing data-independent
memory-hard functions (Vol. 9815, pp. 241–271). Presented at the CRYPTO: International
Cryptology Conference, Santa Barbara, CA, USA: Springer. https://doi.org/10.1007/978-3-662-53008-5_9'
chicago: Alwen, Joel F, and Jeremiah Blocki. “Efficiently Computing Data-Independent
Memory-Hard Functions,” 9815:241–71. Springer, 2016. https://doi.org/10.1007/978-3-662-53008-5_9.
ieee: 'J. F. Alwen and J. Blocki, “Efficiently computing data-independent memory-hard
functions,” presented at the CRYPTO: International Cryptology Conference, Santa
Barbara, CA, USA, 2016, vol. 9815, pp. 241–271.'
ista: 'Alwen JF, Blocki J. 2016. Efficiently computing data-independent memory-hard
functions. CRYPTO: International Cryptology Conference, LNCS, vol. 9815, 241–271.'
mla: Alwen, Joel F., and Jeremiah Blocki. Efficiently Computing Data-Independent
Memory-Hard Functions. Vol. 9815, Springer, 2016, pp. 241–71, doi:10.1007/978-3-662-53008-5_9.
short: J.F. Alwen, J. Blocki, in:, Springer, 2016, pp. 241–271.
conference:
end_date: 2016-08-18
location: Santa Barbara, CA, USA
name: 'CRYPTO: International Cryptology Conference'
start_date: 2016-08-14
date_created: 2018-12-11T11:51:36Z
date_published: 2016-08-01T00:00:00Z
date_updated: 2021-01-12T06:50:11Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-662-53008-5_9
intvolume: ' 9815'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://eprint.iacr.org/2016/115
month: '08'
oa: 1
oa_version: Preprint
page: 241 - 271
publication_status: published
publisher: Springer
publist_id: '5876'
quality_controlled: '1'
scopus_import: 1
status: public
title: Efficiently computing data-independent memory-hard functions
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 9815
year: '2016'
...
---
_id: '1366'
abstract:
- lang: eng
text: 'We study the problem of devising provably secure PRNGs with input based on
the sponge paradigm. Such constructions are very appealing, as efficient software/hardware
implementations of SHA-3 can easily be translated into a PRNG in a nearly black-box
way. The only existing sponge-based construction, proposed by Bertoni et al. (CHES
2010), fails to achieve the security notion of robustness recently considered
by Dodis et al. (CCS 2013), for two reasons: (1) The construction is deterministic,
and thus there are high-entropy input distributions on which the construction
fails to extract random bits, and (2) The construction is not forward secure,
and presented solutions aiming at restoring forward security have not been rigorously
analyzed. We propose a seeded variant of Bertoni et al.’s PRNG with input which
we prove secure in the sense of robustness, delivering in particular concrete
security bounds. On the way, we make what we believe to be an important conceptual
contribution, developing a variant of the security framework of Dodis et al. tailored
at the ideal permutation model that captures PRNG security in settings where the
weakly random inputs are provided from a large class of possible adversarial samplers
which are also allowed to query the random permutation. As a further application
of our techniques, we also present an efficient sponge-based key-derivation function
(which can be instantiated from SHA-3 in a black-box fashion), which we also prove
secure when fed with samples from permutation-dependent distributions.'
alternative_title:
- LNCS
author:
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: 'Gazi P, Tessaro S. Provably robust sponge-based PRNGs and KDFs. In: Vol 9665.
Springer; 2016:87-116. doi:10.1007/978-3-662-49890-3_4'
apa: 'Gazi, P., & Tessaro, S. (2016). Provably robust sponge-based PRNGs and
KDFs (Vol. 9665, pp. 87–116). Presented at the EUROCRYPT: Theory and Applications
of Cryptographic Techniques, Vienna, Austria: Springer. https://doi.org/10.1007/978-3-662-49890-3_4'
chicago: Gazi, Peter, and Stefano Tessaro. “Provably Robust Sponge-Based PRNGs and
KDFs,” 9665:87–116. Springer, 2016. https://doi.org/10.1007/978-3-662-49890-3_4.
ieee: 'P. Gazi and S. Tessaro, “Provably robust sponge-based PRNGs and KDFs,” presented
at the EUROCRYPT: Theory and Applications of Cryptographic Techniques, Vienna,
Austria, 2016, vol. 9665, pp. 87–116.'
ista: 'Gazi P, Tessaro S. 2016. Provably robust sponge-based PRNGs and KDFs. EUROCRYPT:
Theory and Applications of Cryptographic Techniques, LNCS, vol. 9665, 87–116.'
mla: Gazi, Peter, and Stefano Tessaro. Provably Robust Sponge-Based PRNGs and
KDFs. Vol. 9665, Springer, 2016, pp. 87–116, doi:10.1007/978-3-662-49890-3_4.
short: P. Gazi, S. Tessaro, in:, Springer, 2016, pp. 87–116.
conference:
end_date: 2016-05-12
location: Vienna, Austria
name: 'EUROCRYPT: Theory and Applications of Cryptographic Techniques'
start_date: 2016-05-08
date_created: 2018-12-11T11:51:36Z
date_published: 2016-05-01T00:00:00Z
date_updated: 2021-01-12T06:50:11Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-662-49890-3_4
ec_funded: 1
intvolume: ' 9665'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/169/20160219:201940
month: '05'
oa: 1
oa_version: Preprint
page: 87 - 116
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5872'
quality_controlled: '1'
scopus_import: 1
status: public
title: Provably robust sponge-based PRNGs and KDFs
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 9665
year: '2016'
...
---
_id: '1592'
abstract:
- lang: eng
text: A modular approach to constructing cryptographic protocols leads to simple
designs but often inefficient instantiations. On the other hand, ad hoc constructions
may yield efficient protocols at the cost of losing conceptual simplicity. We
suggest a new design paradigm, structure-preserving cryptography, that provides
a way to construct modular protocols with reasonable efficiency while retaining
conceptual simplicity. A cryptographic scheme over a bilinear group is called
structure-preserving if its public inputs and outputs consist of elements from
the bilinear groups and their consistency can be verified by evaluating pairing-product
equations. As structure-preserving schemes smoothly interoperate with each other,
they are useful as building blocks in modular design of cryptographic applications.
This paper introduces structure-preserving commitment and signature schemes over
bilinear groups with several desirable properties. The commitment schemes include
homomorphic, trapdoor and length-reducing commitments to group elements, and the
structure-preserving signature schemes are the first ones that yield constant-size
signatures on multiple group elements. A structure-preserving signature scheme
is called automorphic if the public keys lie in the message space, which cannot
be achieved by compressing inputs via a cryptographic hash function, as this would
destroy the mathematical structure we are trying to preserve. Automorphic signatures
can be used for building certification chains underlying privacy-preserving protocols.
Among a vast number of applications of structure-preserving protocols, we present
an efficient round-optimal blind-signature scheme and a group signature scheme
with an efficient and concurrently secure protocol for enrolling new members.
acknowledgement: The authors would like to thank the anonymous reviewers of this paper.
We also would like to express our appreciation to the program committee and the
anonymous reviewers for CRYPTO 2010. The first author thanks Sherman S. M. Chow
for his comment on group signatures in Sect. 7.1.
author:
- first_name: Masayuki
full_name: Abe, Masayuki
last_name: Abe
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Jens
full_name: Groth, Jens
last_name: Groth
- first_name: Kristiyan
full_name: Haralambiev, Kristiyan
last_name: Haralambiev
- first_name: Miyako
full_name: Ohkubo, Miyako
last_name: Ohkubo
citation:
ama: Abe M, Fuchsbauer G, Groth J, Haralambiev K, Ohkubo M. Structure preserving
signatures and commitments to group elements. Journal of Cryptology. 2016;29(2):363-421.
doi:10.1007/s00145-014-9196-7
apa: Abe, M., Fuchsbauer, G., Groth, J., Haralambiev, K., & Ohkubo, M. (2016).
Structure preserving signatures and commitments to group elements. Journal
of Cryptology. Springer. https://doi.org/10.1007/s00145-014-9196-7
chicago: Abe, Masayuki, Georg Fuchsbauer, Jens Groth, Kristiyan Haralambiev, and
Miyako Ohkubo. “Structure Preserving Signatures and Commitments to Group Elements.”
Journal of Cryptology. Springer, 2016. https://doi.org/10.1007/s00145-014-9196-7.
ieee: M. Abe, G. Fuchsbauer, J. Groth, K. Haralambiev, and M. Ohkubo, “Structure
preserving signatures and commitments to group elements,” Journal of Cryptology,
vol. 29, no. 2. Springer, pp. 363–421, 2016.
ista: Abe M, Fuchsbauer G, Groth J, Haralambiev K, Ohkubo M. 2016. Structure preserving
signatures and commitments to group elements. Journal of Cryptology. 29(2), 363–421.
mla: Abe, Masayuki, et al. “Structure Preserving Signatures and Commitments to Group
Elements.” Journal of Cryptology, vol. 29, no. 2, Springer, 2016, pp. 363–421,
doi:10.1007/s00145-014-9196-7.
short: M. Abe, G. Fuchsbauer, J. Groth, K. Haralambiev, M. Ohkubo, Journal of Cryptology
29 (2016) 363–421.
date_created: 2018-12-11T11:52:54Z
date_published: 2016-04-01T00:00:00Z
date_updated: 2021-01-12T06:51:49Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/s00145-014-9196-7
intvolume: ' 29'
issue: '2'
language:
- iso: eng
month: '04'
oa_version: None
page: 363 - 421
publication: Journal of Cryptology
publication_status: published
publisher: Springer
publist_id: '5579'
quality_controlled: '1'
scopus_import: 1
status: public
title: Structure preserving signatures and commitments to group elements
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 29
year: '2016'
...
---
_id: '1225'
abstract:
- lang: eng
text: At Crypto 2015 Fuchsbauer, Hanser and Slamanig (FHS) presented the first standard-model
construction of efficient roundoptimal blind signatures that does not require
complexity leveraging. It is conceptually simple and builds on the primitive of
structure-preserving signatures on equivalence classes (SPS-EQ). FHS prove the
unforgeability of their scheme assuming EUF-CMA security of the SPS-EQ scheme
and hardness of a version of the DH inversion problem. Blindness under adversarially
chosen keys is proven under an interactive variant of the DDH assumption. We propose
a variant of their scheme whose blindness can be proven under a non-interactive
assumption, namely a variant of the bilinear DDH assumption. We moreover prove
its unforgeability assuming only unforgeability of the underlying SPS-EQ but no
additional assumptions as needed for the FHS scheme.
alternative_title:
- LNCS
author:
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Christian
full_name: Hanser, Christian
last_name: Hanser
- first_name: Chethan
full_name: Kamath Hosdurg, Chethan
id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87
last_name: Kamath Hosdurg
- first_name: Daniel
full_name: Slamanig, Daniel
last_name: Slamanig
citation:
ama: 'Fuchsbauer G, Hanser C, Kamath Hosdurg C, Slamanig D. Practical round-optimal
blind signatures in the standard model from weaker assumptions. In: Vol 9841.
Springer; 2016:391-408. doi:10.1007/978-3-319-44618-9_21'
apa: 'Fuchsbauer, G., Hanser, C., Kamath Hosdurg, C., & Slamanig, D. (2016).
Practical round-optimal blind signatures in the standard model from weaker assumptions
(Vol. 9841, pp. 391–408). Presented at the SCN: Security and Cryptography for
Networks, Amalfi, Italy: Springer. https://doi.org/10.1007/978-3-319-44618-9_21'
chicago: Fuchsbauer, Georg, Christian Hanser, Chethan Kamath Hosdurg, and Daniel
Slamanig. “Practical Round-Optimal Blind Signatures in the Standard Model from
Weaker Assumptions,” 9841:391–408. Springer, 2016. https://doi.org/10.1007/978-3-319-44618-9_21.
ieee: 'G. Fuchsbauer, C. Hanser, C. Kamath Hosdurg, and D. Slamanig, “Practical
round-optimal blind signatures in the standard model from weaker assumptions,”
presented at the SCN: Security and Cryptography for Networks, Amalfi, Italy, 2016,
vol. 9841, pp. 391–408.'
ista: 'Fuchsbauer G, Hanser C, Kamath Hosdurg C, Slamanig D. 2016. Practical round-optimal
blind signatures in the standard model from weaker assumptions. SCN: Security
and Cryptography for Networks, LNCS, vol. 9841, 391–408.'
mla: Fuchsbauer, Georg, et al. Practical Round-Optimal Blind Signatures in the
Standard Model from Weaker Assumptions. Vol. 9841, Springer, 2016, pp. 391–408,
doi:10.1007/978-3-319-44618-9_21.
short: G. Fuchsbauer, C. Hanser, C. Kamath Hosdurg, D. Slamanig, in:, Springer,
2016, pp. 391–408.
conference:
end_date: 2016-09-02
location: Amalfi, Italy
name: 'SCN: Security and Cryptography for Networks'
start_date: 2016-08-31
date_created: 2018-12-11T11:50:49Z
date_published: 2016-08-11T00:00:00Z
date_updated: 2023-02-23T10:08:16Z
day: '11'
department:
- _id: KrPi
doi: 10.1007/978-3-319-44618-9_21
ec_funded: 1
intvolume: ' 9841'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/662
month: '08'
oa: 1
oa_version: Submitted Version
page: 391 - 408
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_status: published
publisher: Springer
publist_id: '6109'
quality_controlled: '1'
related_material:
record:
- id: '1647'
relation: earlier_version
status: public
scopus_import: 1
status: public
title: Practical round-optimal blind signatures in the standard model from weaker
assumptions
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9841
year: '2016'
...
---
_id: '1653'
abstract:
- lang: eng
text: "A somewhere statistically binding (SSB) hash, introduced by Hubáček and Wichs
(ITCS ’15), can be used to hash a long string x to a short digest y = H hk (x)
using a public hashing-key hk. Furthermore, there is a way to set up the hash
key hk to make it statistically binding on some arbitrary hidden position i, meaning
that: (1) the digest y completely determines the i’th bit (or symbol) of x so
that all pre-images of y have the same value in the i’th position, (2) it is computationally
infeasible to distinguish the position i on which hk is statistically binding
from any other position i’. Lastly, the hash should have a local opening property
analogous to Merkle-Tree hashing, meaning that given x and y = H hk (x) it should
be possible to create a short proof π that certifies the value of the i’th bit
(or symbol) of x without having to provide the entire input x. A similar primitive
called a positional accumulator, introduced by Koppula, Lewko and Waters (STOC
’15) further supports dynamic updates of the hashed value. These tools, which
are interesting in their own right, also serve as one of the main technical components
in several recent works building advanced applications from indistinguishability
obfuscation (iO).\r\n\r\nThe prior constructions of SSB hashing and positional
accumulators required fully homomorphic encryption (FHE) and iO respectively.
In this work, we give new constructions of these tools based on well studied number-theoretic
assumptions such as DDH, Phi-Hiding and DCR, as well as a general construction
from lossy/injective functions."
alternative_title:
- LNCS
author:
- first_name: Tatsuaki
full_name: Okamoto, Tatsuaki
last_name: Okamoto
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Brent
full_name: Waters, Brent
last_name: Waters
- first_name: Daniel
full_name: Wichs, Daniel
last_name: Wichs
citation:
ama: 'Okamoto T, Pietrzak KZ, Waters B, Wichs D. New realizations of somewhere statistically
binding hashing and positional accumulators. In: Vol 9452. Springer; 2016:121-145.
doi:10.1007/978-3-662-48797-6_6'
apa: 'Okamoto, T., Pietrzak, K. Z., Waters, B., & Wichs, D. (2016). New realizations
of somewhere statistically binding hashing and positional accumulators (Vol. 9452,
pp. 121–145). Presented at the ASIACRYPT: Theory and Application of Cryptology
and Information Security, Auckland, New Zealand: Springer. https://doi.org/10.1007/978-3-662-48797-6_6'
chicago: Okamoto, Tatsuaki, Krzysztof Z Pietrzak, Brent Waters, and Daniel Wichs.
“New Realizations of Somewhere Statistically Binding Hashing and Positional Accumulators,”
9452:121–45. Springer, 2016. https://doi.org/10.1007/978-3-662-48797-6_6.
ieee: 'T. Okamoto, K. Z. Pietrzak, B. Waters, and D. Wichs, “New realizations of
somewhere statistically binding hashing and positional accumulators,” presented
at the ASIACRYPT: Theory and Application of Cryptology and Information Security,
Auckland, New Zealand, 2016, vol. 9452, pp. 121–145.'
ista: 'Okamoto T, Pietrzak KZ, Waters B, Wichs D. 2016. New realizations of somewhere
statistically binding hashing and positional accumulators. ASIACRYPT: Theory and
Application of Cryptology and Information Security, LNCS, vol. 9452, 121–145.'
mla: Okamoto, Tatsuaki, et al. New Realizations of Somewhere Statistically Binding
Hashing and Positional Accumulators. Vol. 9452, Springer, 2016, pp. 121–45,
doi:10.1007/978-3-662-48797-6_6.
short: T. Okamoto, K.Z. Pietrzak, B. Waters, D. Wichs, in:, Springer, 2016, pp.
121–145.
conference:
end_date: 2015-12-03
location: Auckland, New Zealand
name: 'ASIACRYPT: Theory and Application of Cryptology and Information Security'
start_date: 2015-11-29
date_created: 2018-12-11T11:53:16Z
date_published: 2016-01-08T00:00:00Z
date_updated: 2021-01-12T06:52:16Z
day: '08'
ddc:
- '000'
department:
- _id: KrPi
doi: 10.1007/978-3-662-48797-6_6
ec_funded: 1
file:
- access_level: open_access
checksum: a57711cb660c5b17b42bb47275a00180
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:12:05Z
date_updated: 2020-07-14T12:45:08Z
file_id: '4923'
file_name: IST-2016-677-v1+1_869.pdf
file_size: 580088
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9452'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Submitted Version
page: 121 - 145
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5497'
pubrep_id: '677'
quality_controlled: '1'
scopus_import: 1
status: public
title: New realizations of somewhere statistically binding hashing and positional
accumulators
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9452
year: '2016'
...
---
_id: '1479'
abstract:
- lang: eng
text: "Most entropy notions H(.) like Shannon or min-entropy satisfy a chain rule
stating that for random variables X,Z, and A we have H(X|Z,A)≥H(X|Z)−|A|. That
is, by conditioning on A the entropy of X can decrease by at most the bitlength
|A| of A. Such chain rules are known to hold for some computational entropy notions
like Yao’s and unpredictability-entropy. For HILL entropy, the computational analogue
of min-entropy, the chain rule is of special interest and has found many applications,
including leakage-resilient cryptography, deterministic encryption, and memory
delegation. These applications rely on restricted special cases of the chain rule.
Whether the chain rule for conditional HILL entropy holds in general was an open
problem for which we give a strong negative answer: we construct joint distributions
(X,Z,A), where A is a distribution over a single bit, such that the HILL entropy
H HILL (X|Z) is large but H HILL (X|Z,A) is basically zero.\r\n\r\nOur counterexample
just makes the minimal assumption that NP⊈P/poly. Under the stronger assumption
that injective one-way function exist, we can make all the distributions efficiently
samplable.\r\n\r\nFinally, we show that some more sophisticated cryptographic
objects like lossy functions can be used to sample a distribution constituting
a counterexample to the chain rule making only a single invocation to the underlying
object."
acknowledgement: "This work was partly funded by the European Research Council under
ERC Starting Grant 259668-PSPC and ERC Advanced Grant 321310-PERCY.\r\n"
author:
- first_name: Stephan
full_name: Krenn, Stephan
id: 329FCCF0-F248-11E8-B48F-1D18A9856A87
last_name: Krenn
orcid: 0000-0003-2835-9093
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Akshay
full_name: Wadia, Akshay
last_name: Wadia
- first_name: Daniel
full_name: Wichs, Daniel
last_name: Wichs
citation:
ama: Krenn S, Pietrzak KZ, Wadia A, Wichs D. A counterexample to the chain rule
for conditional HILL entropy. Computational Complexity. 2016;25(3):567-605.
doi:10.1007/s00037-015-0120-9
apa: Krenn, S., Pietrzak, K. Z., Wadia, A., & Wichs, D. (2016). A counterexample
to the chain rule for conditional HILL entropy. Computational Complexity.
Springer. https://doi.org/10.1007/s00037-015-0120-9
chicago: Krenn, Stephan, Krzysztof Z Pietrzak, Akshay Wadia, and Daniel Wichs. “A
Counterexample to the Chain Rule for Conditional HILL Entropy.” Computational
Complexity. Springer, 2016. https://doi.org/10.1007/s00037-015-0120-9.
ieee: S. Krenn, K. Z. Pietrzak, A. Wadia, and D. Wichs, “A counterexample to the
chain rule for conditional HILL entropy,” Computational Complexity, vol.
25, no. 3. Springer, pp. 567–605, 2016.
ista: Krenn S, Pietrzak KZ, Wadia A, Wichs D. 2016. A counterexample to the chain
rule for conditional HILL entropy. Computational Complexity. 25(3), 567–605.
mla: Krenn, Stephan, et al. “A Counterexample to the Chain Rule for Conditional
HILL Entropy.” Computational Complexity, vol. 25, no. 3, Springer, 2016,
pp. 567–605, doi:10.1007/s00037-015-0120-9.
short: S. Krenn, K.Z. Pietrzak, A. Wadia, D. Wichs, Computational Complexity 25
(2016) 567–605.
date_created: 2018-12-11T11:52:16Z
date_published: 2016-09-01T00:00:00Z
date_updated: 2023-02-23T11:05:09Z
day: '01'
ddc:
- '004'
department:
- _id: KrPi
doi: 10.1007/s00037-015-0120-9
ec_funded: 1
file:
- access_level: open_access
checksum: 7659296174fa75f5f0364f31f46f4bcf
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:13:29Z
date_updated: 2020-07-14T12:44:56Z
file_id: '5012'
file_name: IST-2017-766-v1+1_678.pdf
file_size: 483258
relation: main_file
file_date_updated: 2020-07-14T12:44:56Z
has_accepted_license: '1'
intvolume: ' 25'
issue: '3'
language:
- iso: eng
month: '09'
oa: 1
oa_version: Submitted Version
page: 567 - 605
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: Computational Complexity
publication_status: published
publisher: Springer
publist_id: '5715'
pubrep_id: '766'
quality_controlled: '1'
related_material:
record:
- id: '2940'
relation: earlier_version
status: public
scopus_import: 1
status: public
title: A counterexample to the chain rule for conditional HILL entropy
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 25
year: '2016'
...
---
_id: '1229'
abstract:
- lang: eng
text: Witness encryption (WE) was introduced by Garg et al. [GGSW13]. A WE scheme
is defined for some NP language L and lets a sender encrypt messages relative
to instances x. A ciphertext for x can be decrypted using w witnessing x ∈ L,
but hides the message if x ∈ L. Garg et al. construct WE from multilinear maps
and give another construction [GGH+13b] using indistinguishability obfuscation
(iO) for circuits. Due to the reliance on such heavy tools, WE can cur- rently
hardly be implemented on powerful hardware and will unlikely be realizable on
constrained devices like smart cards any time soon. We construct a WE scheme where
encryption is done by simply computing a Naor-Yung ciphertext (two CPA encryptions
and a NIZK proof). To achieve this, our scheme has a setup phase, which outputs
public parameters containing an obfuscated circuit (only required for decryption),
two encryption keys and a common reference string (used for encryption). This
setup need only be run once, and the parame- ters can be used for arbitrary many
encryptions. Our scheme can also be turned into a functional WE scheme, where
a message is encrypted w.r.t. a statement and a function f, and decryption with
a witness w yields f (m, w). Our construction is inspired by the functional encryption
scheme by Garg et al. and we prove (selective) security assuming iO and statistically
simulation-sound NIZK. We give a construction of the latter in bilinear groups
and combining it with ElGamal encryption, our ciphertexts are of size 1.3 kB at
a 128-bit security level and can be computed on a smart card.
acknowledgement: Research supported by the European Research Council, ERC starting grant
(259668-PSPC) and ERC consolidator grant (682815 - TOCNeT).
alternative_title:
- LNCS
author:
- first_name: Hamza M
full_name: Abusalah, Hamza M
id: 40297222-F248-11E8-B48F-1D18A9856A87
last_name: Abusalah
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Abusalah HM, Fuchsbauer G, Pietrzak KZ. Offline witness encryption. In: Vol
9696. Springer; 2016:285-303. doi:10.1007/978-3-319-39555-5_16'
apa: 'Abusalah, H. M., Fuchsbauer, G., & Pietrzak, K. Z. (2016). Offline witness
encryption (Vol. 9696, pp. 285–303). Presented at the ACNS: Applied Cryptography
and Network Security, Guildford, UK: Springer. https://doi.org/10.1007/978-3-319-39555-5_16'
chicago: Abusalah, Hamza M, Georg Fuchsbauer, and Krzysztof Z Pietrzak. “Offline
Witness Encryption,” 9696:285–303. Springer, 2016. https://doi.org/10.1007/978-3-319-39555-5_16.
ieee: 'H. M. Abusalah, G. Fuchsbauer, and K. Z. Pietrzak, “Offline witness encryption,”
presented at the ACNS: Applied Cryptography and Network Security, Guildford, UK,
2016, vol. 9696, pp. 285–303.'
ista: 'Abusalah HM, Fuchsbauer G, Pietrzak KZ. 2016. Offline witness encryption.
ACNS: Applied Cryptography and Network Security, LNCS, vol. 9696, 285–303.'
mla: Abusalah, Hamza M., et al. Offline Witness Encryption. Vol. 9696, Springer,
2016, pp. 285–303, doi:10.1007/978-3-319-39555-5_16.
short: H.M. Abusalah, G. Fuchsbauer, K.Z. Pietrzak, in:, Springer, 2016, pp. 285–303.
conference:
end_date: 2016-06-22
location: Guildford, UK
name: 'ACNS: Applied Cryptography and Network Security'
start_date: 2016-06-19
date_created: 2018-12-11T11:50:50Z
date_published: 2016-06-09T00:00:00Z
date_updated: 2023-09-07T12:30:22Z
day: '09'
ddc:
- '005'
- '600'
department:
- _id: KrPi
doi: 10.1007/978-3-319-39555-5_16
ec_funded: 1
file:
- access_level: open_access
checksum: 34fa9ce681da845a1ba945ba3dc57867
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:17:20Z
date_updated: 2020-07-14T12:44:39Z
file_id: '5273'
file_name: IST-2017-765-v1+1_838.pdf
file_size: 515000
relation: main_file
file_date_updated: 2020-07-14T12:44:39Z
has_accepted_license: '1'
intvolume: ' 9696'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Submitted Version
page: 285 - 303
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_status: published
publisher: Springer
publist_id: '6105'
pubrep_id: '765'
quality_controlled: '1'
related_material:
record:
- id: '83'
relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Offline witness encryption
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9696
year: '2016'
...
---
_id: '1236'
abstract:
- lang: eng
text: 'A constrained pseudorandom function F: K × X → Y for a family T ⊆ 2X of subsets
of X is a function where for any key k ∈ K and set S ∈ T one can efficiently compute
a constrained key kS which allows to evaluate F (k, ·) on all inputs x ∈ S, while
even given this key, the outputs on all inputs x ∉ S look random. At Asiacrypt’13
Boneh and Waters gave a construction which supports the most general set family
so far. Its keys kc are defined for sets decided by boolean circuits C and enable
evaluation of the PRF on any x ∈ X where C(x) = 1. In their construction the PRF
input length and the size of the circuits C for which constrained keys can be
computed must be fixed beforehand during key generation. We construct a constrained
PRF that has an unbounded input length and whose constrained keys can be defined
for any set recognized by a Turing machine. The only a priori bound we make is
on the description size of the machines. We prove our construction secure assuming
publiccoin differing-input obfuscation. As applications of our constrained PRF
we build a broadcast encryption scheme where the number of potential receivers
need not be fixed at setup (in particular, the length of the keys is independent
of the number of parties) and the first identity-based non-interactive key exchange
protocol with no bound on the number of parties that can agree on a shared key.'
acknowledgement: Supported by the European Research Council, ERC Starting Grant (259668-PSPC).
alternative_title:
- LNCS
author:
- first_name: Hamza M
full_name: Abusalah, Hamza M
id: 40297222-F248-11E8-B48F-1D18A9856A87
last_name: Abusalah
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Abusalah HM, Fuchsbauer G, Pietrzak KZ. Constrained PRFs for unbounded inputs.
In: Vol 9610. Springer; 2016:413-428. doi:10.1007/978-3-319-29485-8_24'
apa: 'Abusalah, H. M., Fuchsbauer, G., & Pietrzak, K. Z. (2016). Constrained
PRFs for unbounded inputs (Vol. 9610, pp. 413–428). Presented at the CT-RSA: Topics
in Cryptology, San Francisco, CA, USA: Springer. https://doi.org/10.1007/978-3-319-29485-8_24'
chicago: Abusalah, Hamza M, Georg Fuchsbauer, and Krzysztof Z Pietrzak. “Constrained
PRFs for Unbounded Inputs,” 9610:413–28. Springer, 2016. https://doi.org/10.1007/978-3-319-29485-8_24.
ieee: 'H. M. Abusalah, G. Fuchsbauer, and K. Z. Pietrzak, “Constrained PRFs for
unbounded inputs,” presented at the CT-RSA: Topics in Cryptology, San Francisco,
CA, USA, 2016, vol. 9610, pp. 413–428.'
ista: 'Abusalah HM, Fuchsbauer G, Pietrzak KZ. 2016. Constrained PRFs for unbounded
inputs. CT-RSA: Topics in Cryptology, LNCS, vol. 9610, 413–428.'
mla: Abusalah, Hamza M., et al. Constrained PRFs for Unbounded Inputs. Vol.
9610, Springer, 2016, pp. 413–28, doi:10.1007/978-3-319-29485-8_24.
short: H.M. Abusalah, G. Fuchsbauer, K.Z. Pietrzak, in:, Springer, 2016, pp. 413–428.
conference:
end_date: 2016-03-04
location: San Francisco, CA, USA
name: 'CT-RSA: Topics in Cryptology'
start_date: 2016-02-29
date_created: 2018-12-11T11:50:52Z
date_published: 2016-02-02T00:00:00Z
date_updated: 2023-09-07T12:30:22Z
day: '02'
ddc:
- '005'
- '600'
department:
- _id: KrPi
doi: 10.1007/978-3-319-29485-8_24
ec_funded: 1
file:
- access_level: open_access
checksum: 3851cee49933ae13b1272e516f213e13
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:08:05Z
date_updated: 2020-07-14T12:44:41Z
file_id: '4664'
file_name: IST-2017-764-v1+1_279.pdf
file_size: 495176
relation: main_file
file_date_updated: 2020-07-14T12:44:41Z
has_accepted_license: '1'
intvolume: ' 9610'
language:
- iso: eng
month: '02'
oa: 1
oa_version: Submitted Version
page: 413 - 428
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '6097'
pubrep_id: '764'
quality_controlled: '1'
related_material:
record:
- id: '83'
relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Constrained PRFs for unbounded inputs
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9610
year: '2016'
...
---
_id: '1235'
abstract:
- lang: eng
text: 'A constrained pseudorandom function (CPRF) F: K×X → Y for a family T of subsets
of χ is a function where for any key k ∈ K and set S ∈ T one can efficiently compute
a short constrained key kS, which allows to evaluate F(k, ·) on all inputs x ∈
S, while the outputs on all inputs x /∈ S look random even given kS. Abusalah
et al. recently constructed the first constrained PRF for inputs of arbitrary
length whose sets S are decided by Turing machines. They use their CPRF to build
broadcast encryption and the first ID-based non-interactive key exchange for an
unbounded number of users. Their constrained keys are obfuscated circuits and
are therefore large. In this work we drastically reduce the key size and define
a constrained key for a Turing machine M as a short signature on M. For this,
we introduce a new signature primitive with constrained signing keys that let
one only sign certain messages, while forging a signature on others is hard even
when knowing the coins for key generation.'
acknowledgement: H. Abusalah—Research supported by the European Research Council,
ERC starting grant (259668-PSPC) and ERC consolidator grant (682815 - TOCNeT).
alternative_title:
- LNCS
author:
- first_name: Hamza M
full_name: Abusalah, Hamza M
id: 40297222-F248-11E8-B48F-1D18A9856A87
last_name: Abusalah
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
citation:
ama: 'Abusalah HM, Fuchsbauer G. Constrained PRFs for unbounded inputs with short
keys. In: Vol 9696. Springer; 2016:445-463. doi:10.1007/978-3-319-39555-5_24'
apa: 'Abusalah, H. M., & Fuchsbauer, G. (2016). Constrained PRFs for unbounded
inputs with short keys (Vol. 9696, pp. 445–463). Presented at the ACNS: Applied
Cryptography and Network Security, Guildford, UK: Springer. https://doi.org/10.1007/978-3-319-39555-5_24'
chicago: Abusalah, Hamza M, and Georg Fuchsbauer. “Constrained PRFs for Unbounded
Inputs with Short Keys,” 9696:445–63. Springer, 2016. https://doi.org/10.1007/978-3-319-39555-5_24.
ieee: 'H. M. Abusalah and G. Fuchsbauer, “Constrained PRFs for unbounded inputs
with short keys,” presented at the ACNS: Applied Cryptography and Network Security,
Guildford, UK, 2016, vol. 9696, pp. 445–463.'
ista: 'Abusalah HM, Fuchsbauer G. 2016. Constrained PRFs for unbounded inputs with
short keys. ACNS: Applied Cryptography and Network Security, LNCS, vol. 9696,
445–463.'
mla: Abusalah, Hamza M., and Georg Fuchsbauer. Constrained PRFs for Unbounded
Inputs with Short Keys. Vol. 9696, Springer, 2016, pp. 445–63, doi:10.1007/978-3-319-39555-5_24.
short: H.M. Abusalah, G. Fuchsbauer, in:, Springer, 2016, pp. 445–463.
conference:
end_date: 2016-06-22
location: Guildford, UK
name: 'ACNS: Applied Cryptography and Network Security'
start_date: 2016-06-19
date_created: 2018-12-11T11:50:52Z
date_published: 2016-01-01T00:00:00Z
date_updated: 2023-09-07T12:30:22Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-319-39555-5_24
ec_funded: 1
intvolume: ' 9696'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2016/279.pdf
month: '01'
oa: 1
oa_version: Submitted Version
page: 445 - 463
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '682815'
name: Teaching Old Crypto New Tricks
publication_status: published
publisher: Springer
publist_id: '6098'
quality_controlled: '1'
related_material:
record:
- id: '83'
relation: dissertation_contains
status: public
scopus_import: 1
status: public
title: Constrained PRFs for unbounded inputs with short keys
type: conference
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 9696
year: '2016'
...
---
_id: '1474'
abstract:
- lang: eng
text: Cryptographic access control offers selective access to encrypted data via
a combination of key management and functionality-rich cryptographic schemes,
such as attribute-based encryption. Using this approach, publicly available meta-data
may inadvertently leak information on the access policy that is enforced by cryptography,
which renders cryptographic access control unusable in settings where this information
is highly sensitive. We begin to address this problem by presenting rigorous definitions
for policy privacy in cryptographic access control. For concreteness we set our
results in the model of Role-Based Access Control (RBAC), where we identify and
formalize several different flavors of privacy, however, our framework should
serve as inspiration for other models of access control. Based on our insights
we propose a new system which significantly improves on the privacy properties
of state-of-the-art constructions. Our design is based on a novel type of privacy-preserving
attribute-based encryption, which we introduce and show how to instantiate. We
present our results in the context of a cryptographic RBAC system by Ferrara et
al. (CSF'13), which uses cryptography to control read access to files, while write
access is still delegated to trusted monitors. We give an extension of the construction
that permits cryptographic control over write access. Our construction assumes
that key management uses out-of-band channels between the policy enforcer and
the users but eliminates completely the need for monitoring read/write access
to the data.
article_processing_charge: No
author:
- first_name: Anna
full_name: Ferrara, Anna
last_name: Ferrara
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Bin
full_name: Liu, Bin
last_name: Liu
- first_name: Bogdan
full_name: Warinschi, Bogdan
last_name: Warinschi
citation:
ama: 'Ferrara A, Fuchsbauer G, Liu B, Warinschi B. Policy privacy in cryptographic
access control. In: IEEE; 2015:46-60. doi:10.1109/CSF.2015.11'
apa: 'Ferrara, A., Fuchsbauer, G., Liu, B., & Warinschi, B. (2015). Policy privacy
in cryptographic access control (pp. 46–60). Presented at the CSF: Computer Security
Foundations, Verona, Italy: IEEE. https://doi.org/10.1109/CSF.2015.11'
chicago: Ferrara, Anna, Georg Fuchsbauer, Bin Liu, and Bogdan Warinschi. “Policy
Privacy in Cryptographic Access Control,” 46–60. IEEE, 2015. https://doi.org/10.1109/CSF.2015.11.
ieee: 'A. Ferrara, G. Fuchsbauer, B. Liu, and B. Warinschi, “Policy privacy in cryptographic
access control,” presented at the CSF: Computer Security Foundations, Verona,
Italy, 2015, pp. 46–60.'
ista: 'Ferrara A, Fuchsbauer G, Liu B, Warinschi B. 2015. Policy privacy in cryptographic
access control. CSF: Computer Security Foundations, 46–60.'
mla: Ferrara, Anna, et al. Policy Privacy in Cryptographic Access Control.
IEEE, 2015, pp. 46–60, doi:10.1109/CSF.2015.11.
short: A. Ferrara, G. Fuchsbauer, B. Liu, B. Warinschi, in:, IEEE, 2015, pp. 46–60.
conference:
end_date: 2015-07-17
location: Verona, Italy
name: 'CSF: Computer Security Foundations'
start_date: 2015-07-13
date_created: 2018-12-11T11:52:14Z
date_published: 2015-09-04T00:00:00Z
date_updated: 2021-01-12T06:50:59Z
day: '04'
department:
- _id: KrPi
doi: 10.1109/CSF.2015.11
ec_funded: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://epubs.surrey.ac.uk/808055/
month: '09'
oa: 1
oa_version: Submitted Version
page: 46-60
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: IEEE
publist_id: '5722'
quality_controlled: '1'
status: public
title: Policy privacy in cryptographic access control
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2015'
...
---
_id: '1646'
abstract:
- lang: eng
text: 'A pseudorandom function (PRF) is a keyed function F : K × X → Y where, for
a random key k ∈ K, the function F(k, ·) is indistinguishable from a uniformly
random function, given black-box access. A key-homomorphic PRF has the additional
feature that for any keys k, k'' and any input x, we have F(k+k'', x) = F(k, x)⊕F(k'',
x) for some group operations +,⊕ on K and Y, respectively. A constrained PRF for
a family of setsS ⊆ P(X) has the property that, given any key k and set S ∈ S,
one can efficiently compute a “constrained” key kS that enables evaluation of
F(k, x) on all inputs x ∈ S, while the values F(k, x) for x /∈ S remain pseudorandom
even given kS. In this paper we construct PRFs that are simultaneously constrained
and key homomorphic, where the homomorphic property holds even for constrained
keys. We first show that the multilinear map-based bit-fixing and circuit-constrained
PRFs of Boneh and Waters (Asiacrypt 2013) can be modified to also be keyhomomorphic.
We then show that the LWE-based key-homomorphic PRFs of Banerjee and Peikert (Crypto
2014) are essentially already prefix-constrained PRFs, using a (non-obvious) definition
of constrained keys and associated group operation. Moreover, the constrained
keys themselves are pseudorandom, and the constraining and evaluation functions
can all be computed in low depth. As an application of key-homomorphic constrained
PRFs,we construct a proxy re-encryption schemewith fine-grained access control.
This scheme allows storing encrypted data on an untrusted server, where each file
can be encrypted relative to some attributes, so that only parties whose constrained
keys match the attributes can decrypt. Moreover, the server can re-key (arbitrary
subsets of) the ciphertexts without learning anything about the plaintexts, thus
permitting efficient and finegrained revocation.'
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Abishek
full_name: Banerjee, Abishek
last_name: Banerjee
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Chris
full_name: Peikert, Chris
last_name: Peikert
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Sophie
full_name: Stevens, Sophie
last_name: Stevens
citation:
ama: 'Banerjee A, Fuchsbauer G, Peikert C, Pietrzak KZ, Stevens S. Key-homomorphic
constrained pseudorandom functions. In: 12th Theory of Cryptography Conference.
Vol 9015. Springer Nature; 2015:31-60. doi:10.1007/978-3-662-46497-7_2'
apa: 'Banerjee, A., Fuchsbauer, G., Peikert, C., Pietrzak, K. Z., & Stevens,
S. (2015). Key-homomorphic constrained pseudorandom functions. In 12th Theory
of Cryptography Conference (Vol. 9015, pp. 31–60). Warsaw, Poland: Springer
Nature. https://doi.org/10.1007/978-3-662-46497-7_2'
chicago: Banerjee, Abishek, Georg Fuchsbauer, Chris Peikert, Krzysztof Z Pietrzak,
and Sophie Stevens. “Key-Homomorphic Constrained Pseudorandom Functions.” In 12th
Theory of Cryptography Conference, 9015:31–60. Springer Nature, 2015. https://doi.org/10.1007/978-3-662-46497-7_2.
ieee: A. Banerjee, G. Fuchsbauer, C. Peikert, K. Z. Pietrzak, and S. Stevens, “Key-homomorphic
constrained pseudorandom functions,” in 12th Theory of Cryptography Conference,
Warsaw, Poland, 2015, vol. 9015, pp. 31–60.
ista: 'Banerjee A, Fuchsbauer G, Peikert C, Pietrzak KZ, Stevens S. 2015. Key-homomorphic
constrained pseudorandom functions. 12th Theory of Cryptography Conference. TCC:
Theory of Cryptography Conference, LNCS, vol. 9015, 31–60.'
mla: Banerjee, Abishek, et al. “Key-Homomorphic Constrained Pseudorandom Functions.”
12th Theory of Cryptography Conference, vol. 9015, Springer Nature, 2015,
pp. 31–60, doi:10.1007/978-3-662-46497-7_2.
short: A. Banerjee, G. Fuchsbauer, C. Peikert, K.Z. Pietrzak, S. Stevens, in:, 12th
Theory of Cryptography Conference, Springer Nature, 2015, pp. 31–60.
conference:
end_date: 2015-03-25
location: Warsaw, Poland
name: 'TCC: Theory of Cryptography Conference'
start_date: 2015-03-23
date_created: 2018-12-11T11:53:14Z
date_published: 2015-03-01T00:00:00Z
date_updated: 2022-02-03T08:41:46Z
day: '01'
ddc:
- '000'
- '004'
department:
- _id: KrPi
doi: 10.1007/978-3-662-46497-7_2
ec_funded: 1
file:
- access_level: open_access
checksum: 3c5093bda5783c89beaacabf1aa0e60e
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:15:17Z
date_updated: 2020-07-14T12:45:08Z
file_id: '5136'
file_name: IST-2016-679-v1+1_180.pdf
file_size: 450665
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9015'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2015/180
month: '03'
oa: 1
oa_version: Submitted Version
page: 31 - 60
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: 12th Theory of Cryptography Conference
publication_identifier:
isbn:
- 978-3-662-46496-0
publication_status: published
publisher: Springer Nature
publist_id: '5505'
pubrep_id: '679'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Key-homomorphic constrained pseudorandom functions
type: conference
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
volume: 9015
year: '2015'
...
---
_id: '1648'
abstract:
- lang: eng
text: Generalized Selective Decryption (GSD), introduced by Panjwani [TCC’07], is
a game for a symmetric encryption scheme Enc that captures the difficulty of proving
adaptive security of certain protocols, most notably the Logical Key Hierarchy
(LKH) multicast encryption protocol. In the GSD game there are n keys k1,...,
kn, which the adversary may adaptively corrupt (learn); moreover, it can ask for
encryptions Encki (kj) of keys under other keys. The adversary’s task is to distinguish
keys (which it cannot trivially compute) from random. Proving the hardness of
GSD assuming only IND-CPA security of Enc is surprisingly hard. Using “complexity
leveraging” loses a factor exponential in n, which makes the proof practically
meaningless. We can think of the GSD game as building a graph on n vertices, where
we add an edge i → j when the adversary asks for an encryption of kj under ki.
If restricted to graphs of depth ℓ, Panjwani gave a reduction that loses only
a factor exponential in ℓ (not n). To date, this is the only non-trivial result
known for GSD. In this paper we give almost-polynomial reductions for large classes
of graphs. Most importantly, we prove the security of the GSD game restricted
to trees losing only a quasi-polynomial factor n3 log n+5. Trees are an important
special case capturing real-world protocols like the LKH protocol. Our new bound
improves upon Panjwani’s on some LKH variants proposed in the literature where
the underlying tree is not balanced. Our proof builds on ideas from the “nested
hybrids” technique recently introduced by Fuchsbauer et al. [Asiacrypt’14] for
proving the adaptive security of constrained PRFs.
alternative_title:
- LNCS
author:
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Zahra
full_name: Jafargholi, Zahra
last_name: Jafargholi
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Fuchsbauer G, Jafargholi Z, Pietrzak KZ. A quasipolynomial reduction for generalized
selective decryption on trees. In: Vol 9215. Springer; 2015:601-620. doi:10.1007/978-3-662-47989-6_29'
apa: 'Fuchsbauer, G., Jafargholi, Z., & Pietrzak, K. Z. (2015). A quasipolynomial
reduction for generalized selective decryption on trees (Vol. 9215, pp. 601–620).
Presented at the CRYPTO: International Cryptology Conference, Santa Barbara, CA,
USA: Springer. https://doi.org/10.1007/978-3-662-47989-6_29'
chicago: Fuchsbauer, Georg, Zahra Jafargholi, and Krzysztof Z Pietrzak. “A Quasipolynomial
Reduction for Generalized Selective Decryption on Trees,” 9215:601–20. Springer,
2015. https://doi.org/10.1007/978-3-662-47989-6_29.
ieee: 'G. Fuchsbauer, Z. Jafargholi, and K. Z. Pietrzak, “A quasipolynomial reduction
for generalized selective decryption on trees,” presented at the CRYPTO: International
Cryptology Conference, Santa Barbara, CA, USA, 2015, vol. 9215, pp. 601–620.'
ista: 'Fuchsbauer G, Jafargholi Z, Pietrzak KZ. 2015. A quasipolynomial reduction
for generalized selective decryption on trees. CRYPTO: International Cryptology
Conference, LNCS, vol. 9215, 601–620.'
mla: Fuchsbauer, Georg, et al. A Quasipolynomial Reduction for Generalized Selective
Decryption on Trees. Vol. 9215, Springer, 2015, pp. 601–20, doi:10.1007/978-3-662-47989-6_29.
short: G. Fuchsbauer, Z. Jafargholi, K.Z. Pietrzak, in:, Springer, 2015, pp. 601–620.
conference:
end_date: 2015-08-20
location: Santa Barbara, CA, USA
name: 'CRYPTO: International Cryptology Conference'
start_date: 2015-08-16
date_created: 2018-12-11T11:53:14Z
date_published: 2015-08-01T00:00:00Z
date_updated: 2021-01-12T06:52:14Z
day: '01'
ddc:
- '004'
department:
- _id: KrPi
doi: 10.1007/978-3-662-47989-6_29
ec_funded: 1
file:
- access_level: open_access
checksum: 99b76b3263d5082554d0a9cbdeca3a22
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:13:31Z
date_updated: 2020-07-14T12:45:08Z
file_id: '5015'
file_name: IST-2016-674-v1+1_389.pdf
file_size: 505618
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9215'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Submitted Version
page: 601 - 620
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5502'
pubrep_id: '674'
quality_controlled: '1'
scopus_import: 1
status: public
title: A quasipolynomial reduction for generalized selective decryption on trees
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9215
year: '2015'
...
---
_id: '1649'
abstract:
- lang: eng
text: 'We extend a commitment scheme based on the learning with errors over rings
(RLWE) problem, and present efficient companion zeroknowledge proofs of knowledge.
Our scheme maps elements from the ring (or equivalently, n elements from '
alternative_title:
- LNCS
author:
- first_name: Fabrice
full_name: Benhamouda, Fabrice
last_name: Benhamouda
- first_name: Stephan
full_name: Krenn, Stephan
last_name: Krenn
- first_name: Vadim
full_name: Lyubashevsky, Vadim
last_name: Lyubashevsky
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: Benhamouda F, Krenn S, Lyubashevsky V, Pietrzak KZ. Efficient zero-knowledge
proofs for commitments from learning with errors over rings. 2015;9326:305-325.
doi:10.1007/978-3-319-24174-6_16
apa: 'Benhamouda, F., Krenn, S., Lyubashevsky, V., & Pietrzak, K. Z. (2015).
Efficient zero-knowledge proofs for commitments from learning with errors over
rings. Presented at the ESORICS: European Symposium on Research in Computer Security,
Vienna, Austria: Springer. https://doi.org/10.1007/978-3-319-24174-6_16'
chicago: Benhamouda, Fabrice, Stephan Krenn, Vadim Lyubashevsky, and Krzysztof Z
Pietrzak. “Efficient Zero-Knowledge Proofs for Commitments from Learning with
Errors over Rings.” Lecture Notes in Computer Science. Springer, 2015. https://doi.org/10.1007/978-3-319-24174-6_16.
ieee: F. Benhamouda, S. Krenn, V. Lyubashevsky, and K. Z. Pietrzak, “Efficient zero-knowledge
proofs for commitments from learning with errors over rings,” vol. 9326. Springer,
pp. 305–325, 2015.
ista: Benhamouda F, Krenn S, Lyubashevsky V, Pietrzak KZ. 2015. Efficient zero-knowledge
proofs for commitments from learning with errors over rings. 9326, 305–325.
mla: Benhamouda, Fabrice, et al. Efficient Zero-Knowledge Proofs for Commitments
from Learning with Errors over Rings. Vol. 9326, Springer, 2015, pp. 305–25,
doi:10.1007/978-3-319-24174-6_16.
short: F. Benhamouda, S. Krenn, V. Lyubashevsky, K.Z. Pietrzak, 9326 (2015) 305–325.
conference:
end_date: 2015-09-25
location: Vienna, Austria
name: 'ESORICS: European Symposium on Research in Computer Security'
start_date: 2015-09-21
date_created: 2018-12-11T11:53:15Z
date_published: 2015-01-01T00:00:00Z
date_updated: 2021-01-12T06:52:14Z
day: '01'
ddc:
- '000'
- '004'
department:
- _id: KrPi
doi: 10.1007/978-3-319-24174-6_16
ec_funded: 1
file:
- access_level: open_access
checksum: 6eac4a485b2aa644b2d3f753ed0b280b
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:11:28Z
date_updated: 2020-07-14T12:45:08Z
file_id: '4883'
file_name: IST-2016-678-v1+1_889.pdf
file_size: 494239
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9326'
language:
- iso: eng
license: https://creativecommons.org/licenses/by-nc/4.0/
month: '01'
oa: 1
oa_version: Published Version
page: 305 - 325
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5501'
pubrep_id: '678'
quality_controlled: '1'
scopus_import: 1
series_title: Lecture Notes in Computer Science
status: public
title: Efficient zero-knowledge proofs for commitments from learning with errors over
rings
tmp:
image: /images/cc_by_nc.png
legal_code_url: https://creativecommons.org/licenses/by-nc/4.0/legalcode
name: Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
short: CC BY-NC (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9326
year: '2015'
...
---
_id: '1644'
abstract:
- lang: eng
text: Increasing the computational complexity of evaluating a hash function, both
for the honest users as well as for an adversary, is a useful technique employed
for example in password-based cryptographic schemes to impede brute-force attacks,
and also in so-called proofs of work (used in protocols like Bitcoin) to show
that a certain amount of computation was performed by a legitimate user. A natural
approach to adjust the complexity of a hash function is to iterate it c times,
for some parameter c, in the hope that any query to the scheme requires c evaluations
of the underlying hash function. However, results by Dodis et al. (Crypto 2012)
imply that plain iteration falls short of achieving this goal, and designing schemes
which provably have such a desirable property remained an open problem. This paper
formalizes explicitly what it means for a given scheme to amplify the query complexity
of a hash function. In the random oracle model, the goal of a secure query-complexity
amplifier (QCA) scheme is captured as transforming, in the sense of indifferentiability,
a random oracle allowing R queries (for the adversary) into one provably allowing
only r < R queries. Turned around, this means that making r queries to the
scheme requires at least R queries to the actual random oracle. Second, a new
scheme, called collision-free iteration, is proposed and proven to achieve c-fold
QCA for both the honest parties and the adversary, for any fixed parameter c.
alternative_title:
- LNCS
author:
- first_name: Grégory
full_name: Demay, Grégory
last_name: Demay
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Ueli
full_name: Maurer, Ueli
last_name: Maurer
- first_name: Björn
full_name: Tackmann, Björn
last_name: Tackmann
citation:
ama: 'Demay G, Gazi P, Maurer U, Tackmann B. Query-complexity amplification for
random oracles. In: Vol 9063. Springer; 2015:159-180. doi:10.1007/978-3-319-17470-9_10'
apa: 'Demay, G., Gazi, P., Maurer, U., & Tackmann, B. (2015). Query-complexity
amplification for random oracles (Vol. 9063, pp. 159–180). Presented at the ICITS:
International Conference on Information Theoretic Security, Lugano, Switzerland:
Springer. https://doi.org/10.1007/978-3-319-17470-9_10'
chicago: Demay, Grégory, Peter Gazi, Ueli Maurer, and Björn Tackmann. “Query-Complexity
Amplification for Random Oracles,” 9063:159–80. Springer, 2015. https://doi.org/10.1007/978-3-319-17470-9_10.
ieee: 'G. Demay, P. Gazi, U. Maurer, and B. Tackmann, “Query-complexity amplification
for random oracles,” presented at the ICITS: International Conference on Information
Theoretic Security, Lugano, Switzerland, 2015, vol. 9063, pp. 159–180.'
ista: 'Demay G, Gazi P, Maurer U, Tackmann B. 2015. Query-complexity amplification
for random oracles. ICITS: International Conference on Information Theoretic Security,
LNCS, vol. 9063, 159–180.'
mla: Demay, Grégory, et al. Query-Complexity Amplification for Random Oracles.
Vol. 9063, Springer, 2015, pp. 159–80, doi:10.1007/978-3-319-17470-9_10.
short: G. Demay, P. Gazi, U. Maurer, B. Tackmann, in:, Springer, 2015, pp. 159–180.
conference:
end_date: 2015-05-05
location: Lugano, Switzerland
name: 'ICITS: International Conference on Information Theoretic Security'
start_date: 2015-05-02
date_created: 2018-12-11T11:53:13Z
date_published: 2015-01-01T00:00:00Z
date_updated: 2021-01-12T06:52:13Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-319-17470-9_10
ec_funded: 1
intvolume: ' 9063'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://eprint.iacr.org/2015/315
month: '01'
oa: 1
oa_version: Submitted Version
page: 159 - 180
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5507'
quality_controlled: '1'
scopus_import: 1
status: public
title: Query-complexity amplification for random oracles
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9063
year: '2015'
...
---
_id: '1647'
abstract:
- lang: eng
text: Round-optimal blind signatures are notoriously hard to construct in the standard
model, especially in the malicious-signer model, where blindness must hold under
adversarially chosen keys. This is substantiated by several impossibility results.
The only construction that can be termed theoretically efficient, by Garg and
Gupta (Eurocrypt’14), requires complexity leveraging, inducing an exponential
security loss. We present a construction of practically efficient round-optimal
blind signatures in the standard model. It is conceptually simple and builds on
the recent structure-preserving signatures on equivalence classes (SPSEQ) from
Asiacrypt’14. While the traditional notion of blindness follows from standard
assumptions, we prove blindness under adversarially chosen keys under an interactive
variant of DDH. However, we neither require non-uniform assumptions nor complexity
leveraging. We then show how to extend our construction to partially blind signatures
and to blind signatures on message vectors, which yield a construction of one-show
anonymous credentials à la “anonymous credentials light” (CCS’13) in the standard
model. Furthermore, we give the first SPS-EQ construction under noninteractive
assumptions and show how SPS-EQ schemes imply conventional structure-preserving
signatures, which allows us to apply optimality results for the latter to SPS-EQ.
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Christian
full_name: Hanser, Christian
last_name: Hanser
- first_name: Daniel
full_name: Slamanig, Daniel
last_name: Slamanig
citation:
ama: 'Fuchsbauer G, Hanser C, Slamanig D. Practical round-optimal blind signatures
in the standard model. In: Vol 9216. Springer; 2015:233-253. doi:10.1007/978-3-662-48000-7_12'
apa: 'Fuchsbauer, G., Hanser, C., & Slamanig, D. (2015). Practical round-optimal
blind signatures in the standard model (Vol. 9216, pp. 233–253). Presented at
the CRYPTO: International Cryptology Conference, Santa Barbara, CA, United States:
Springer. https://doi.org/10.1007/978-3-662-48000-7_12'
chicago: Fuchsbauer, Georg, Christian Hanser, and Daniel Slamanig. “Practical Round-Optimal
Blind Signatures in the Standard Model,” 9216:233–53. Springer, 2015. https://doi.org/10.1007/978-3-662-48000-7_12.
ieee: 'G. Fuchsbauer, C. Hanser, and D. Slamanig, “Practical round-optimal blind
signatures in the standard model,” presented at the CRYPTO: International Cryptology
Conference, Santa Barbara, CA, United States, 2015, vol. 9216, pp. 233–253.'
ista: 'Fuchsbauer G, Hanser C, Slamanig D. 2015. Practical round-optimal blind signatures
in the standard model. CRYPTO: International Cryptology Conference, LNCS, vol.
9216, 233–253.'
mla: Fuchsbauer, Georg, et al. Practical Round-Optimal Blind Signatures in the
Standard Model. Vol. 9216, Springer, 2015, pp. 233–53, doi:10.1007/978-3-662-48000-7_12.
short: G. Fuchsbauer, C. Hanser, D. Slamanig, in:, Springer, 2015, pp. 233–253.
conference:
end_date: 2015-08-20
location: Santa Barbara, CA, United States
name: 'CRYPTO: International Cryptology Conference'
start_date: 2015-08-16
date_created: 2018-12-11T11:53:14Z
date_published: 2015-08-01T00:00:00Z
date_updated: 2023-02-21T16:44:51Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-662-48000-7_12
ec_funded: 1
intvolume: ' 9216'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2015/626.pdf
month: '08'
oa: 1
oa_version: Submitted Version
page: 233 - 253
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5503'
quality_controlled: '1'
related_material:
record:
- id: '1225'
relation: later_version
status: public
scopus_import: 1
status: public
title: Practical round-optimal blind signatures in the standard model
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9216
year: '2015'
...
---
_id: '1645'
abstract:
- lang: eng
text: Secret-key constructions are often proved secure in a model where one or more
underlying components are replaced by an idealized oracle accessible to the attacker.
This model gives rise to information-theoretic security analyses, and several
advances have been made in this area over the last few years. This paper provides
a systematic overview of what is achievable in this model, and how existing works
fit into this view.
article_number: '7133163'
author:
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: 'Gazi P, Tessaro S. Secret-key cryptography from ideal primitives: A systematic
verview. In: 2015 IEEE Information Theory Workshop. IEEE; 2015. doi:10.1109/ITW.2015.7133163'
apa: 'Gazi, P., & Tessaro, S. (2015). Secret-key cryptography from ideal primitives:
A systematic verview. In 2015 IEEE Information Theory Workshop. Jerusalem,
Israel: IEEE. https://doi.org/10.1109/ITW.2015.7133163'
chicago: 'Gazi, Peter, and Stefano Tessaro. “Secret-Key Cryptography from Ideal
Primitives: A Systematic Verview.” In 2015 IEEE Information Theory Workshop.
IEEE, 2015. https://doi.org/10.1109/ITW.2015.7133163.'
ieee: 'P. Gazi and S. Tessaro, “Secret-key cryptography from ideal primitives: A
systematic verview,” in 2015 IEEE Information Theory Workshop, Jerusalem,
Israel, 2015.'
ista: 'Gazi P, Tessaro S. 2015. Secret-key cryptography from ideal primitives: A
systematic verview. 2015 IEEE Information Theory Workshop. ITW 2015: IEEE Information
Theory Workshop, 7133163.'
mla: 'Gazi, Peter, and Stefano Tessaro. “Secret-Key Cryptography from Ideal Primitives:
A Systematic Verview.” 2015 IEEE Information Theory Workshop, 7133163,
IEEE, 2015, doi:10.1109/ITW.2015.7133163.'
short: P. Gazi, S. Tessaro, in:, 2015 IEEE Information Theory Workshop, IEEE, 2015.
conference:
end_date: 2015-05-01
location: Jerusalem, Israel
name: 'ITW 2015: IEEE Information Theory Workshop'
start_date: 2015-04-26
date_created: 2018-12-11T11:53:13Z
date_published: 2015-06-24T00:00:00Z
date_updated: 2021-01-12T06:52:13Z
day: '24'
department:
- _id: KrPi
doi: 10.1109/ITW.2015.7133163
ec_funded: 1
language:
- iso: eng
month: '06'
oa_version: None
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: 2015 IEEE Information Theory Workshop
publication_status: published
publisher: IEEE
publist_id: '5506'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'Secret-key cryptography from ideal primitives: A systematic verview'
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2015'
...
---
_id: '1654'
abstract:
- lang: eng
text: "HMAC and its variant NMAC are the most popular approaches to deriving a MAC
(and more generally, a PRF) from a cryptographic hash function. Despite nearly
two decades of research, their exact security still remains far from understood
in many different contexts. Indeed, recent works have re-surfaced interest for
{\\em generic} attacks, i.e., attacks that treat the compression function of the
underlying hash function as a black box.\r\n\r\nGeneric security can be proved
in a model where the underlying compression function is modeled as a random function
-- yet, to date, the question of proving tight, non-trivial bounds on the generic
security of HMAC/NMAC even as a PRF remains a challenging open question.\r\n\r\nIn
this paper, we ask the question of whether a small modification to HMAC and NMAC
can allow us to exactly characterize the security of the resulting constructions,
while only incurring little penalty with respect to efficiency. To this end, we
present simple variants of NMAC and HMAC, for which we prove tight bounds on the
generic PRF security, expressed in terms of numbers of construction and compression
function queries necessary to break the construction. All of our constructions
are obtained via a (near) {\\em black-box} modification of NMAC and HMAC, which
can be interpreted as an initial step of key-dependent message pre-processing.\r\n\r\nWhile
our focus is on PRF security, a further attractive feature of our new constructions
is that they clearly defeat all recent generic attacks against properties such
as state recovery and universal forgery. These exploit properties of the so-called
``functional graph'' which are not directly accessible in our new constructions. "
alternative_title:
- LNCS
author:
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: Gazi P, Pietrzak KZ, Tessaro S. Generic security of NMAC and HMAC with input
whitening. 2015;9453:85-109. doi:10.1007/978-3-662-48800-3_4
apa: 'Gazi, P., Pietrzak, K. Z., & Tessaro, S. (2015). Generic security of NMAC
and HMAC with input whitening. Presented at the ASIACRYPT: Theory and Application
of Cryptology and Information Security, Auckland, New Zealand: Springer. https://doi.org/10.1007/978-3-662-48800-3_4'
chicago: Gazi, Peter, Krzysztof Z Pietrzak, and Stefano Tessaro. “Generic Security
of NMAC and HMAC with Input Whitening.” Lecture Notes in Computer Science. Springer,
2015. https://doi.org/10.1007/978-3-662-48800-3_4.
ieee: P. Gazi, K. Z. Pietrzak, and S. Tessaro, “Generic security of NMAC and HMAC
with input whitening,” vol. 9453. Springer, pp. 85–109, 2015.
ista: Gazi P, Pietrzak KZ, Tessaro S. 2015. Generic security of NMAC and HMAC with
input whitening. 9453, 85–109.
mla: Gazi, Peter, et al. Generic Security of NMAC and HMAC with Input Whitening.
Vol. 9453, Springer, 2015, pp. 85–109, doi:10.1007/978-3-662-48800-3_4.
short: P. Gazi, K.Z. Pietrzak, S. Tessaro, 9453 (2015) 85–109.
conference:
end_date: 2015-12-03
location: Auckland, New Zealand
name: 'ASIACRYPT: Theory and Application of Cryptology and Information Security'
start_date: 2015-11-29
date_created: 2018-12-11T11:53:17Z
date_published: 2015-12-30T00:00:00Z
date_updated: 2021-01-12T06:52:16Z
day: '30'
ddc:
- '004'
- '005'
department:
- _id: KrPi
doi: 10.1007/978-3-662-48800-3_4
ec_funded: 1
file:
- access_level: open_access
checksum: d1e53203db2d8573a560995ccdffac62
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:09:09Z
date_updated: 2020-07-14T12:45:08Z
file_id: '4732'
file_name: IST-2016-676-v1+1_881.pdf
file_size: 512071
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9453'
language:
- iso: eng
month: '12'
oa: 1
oa_version: Submitted Version
page: 85 - 109
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5496'
pubrep_id: '676'
quality_controlled: '1'
scopus_import: 1
series_title: Lecture Notes in Computer Science
status: public
title: Generic security of NMAC and HMAC with input whitening
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9453
year: '2015'
...
---
_id: '1650'
abstract:
- lang: eng
text: "We consider the task of deriving a key with high HILL entropy (i.e., being
computationally indistinguishable from a key with high min-entropy) from an unpredictable
source.\r\n\r\nPrevious to this work, the only known way to transform unpredictability
into a key that was ϵ indistinguishable from having min-entropy was via pseudorandomness,
for example by Goldreich-Levin (GL) hardcore bits. This approach has the inherent
limitation that from a source with k bits of unpredictability entropy one can
derive a key of length (and thus HILL entropy) at most k−2log(1/ϵ) bits. In many
settings, e.g. when dealing with biometric data, such a 2log(1/ϵ) bit entropy
loss in not an option. Our main technical contribution is a theorem that states
that in the high entropy regime, unpredictability implies HILL entropy. Concretely,
any variable K with |K|−d bits of unpredictability entropy has the same amount
of so called metric entropy (against real-valued, deterministic distinguishers),
which is known to imply the same amount of HILL entropy. The loss in circuit size
in this argument is exponential in the entropy gap d, and thus this result only
applies for small d (i.e., where the size of distinguishers considered is exponential
in d).\r\n\r\nTo overcome the above restriction, we investigate if it’s possible
to first “condense” unpredictability entropy and make the entropy gap small. We
show that any source with k bits of unpredictability can be condensed into a source
of length k with k−3 bits of unpredictability entropy. Our condenser simply “abuses"
the GL construction and derives a k bit key from a source with k bits of unpredicatibily.
The original GL theorem implies nothing when extracting that many bits, but we
show that in this regime, GL still behaves like a “condenser" for unpredictability.
This result comes with two caveats (1) the loss in circuit size is exponential
in k and (2) we require that the source we start with has no HILL entropy (equivalently,
one can efficiently check if a guess is correct). We leave it as an intriguing
open problem to overcome these restrictions or to prove they’re inherent."
alternative_title:
- LNCS
author:
- first_name: Maciej
full_name: Skórski, Maciej
last_name: Skórski
- first_name: Alexander
full_name: Golovnev, Alexander
last_name: Golovnev
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
citation:
ama: 'Skórski M, Golovnev A, Pietrzak KZ. Condensed unpredictability . In: Vol 9134.
Springer; 2015:1046-1057. doi:10.1007/978-3-662-47672-7_85'
apa: 'Skórski, M., Golovnev, A., & Pietrzak, K. Z. (2015). Condensed unpredictability (Vol.
9134, pp. 1046–1057). Presented at the ICALP: Automata, Languages and Programming,
Kyoto, Japan: Springer. https://doi.org/10.1007/978-3-662-47672-7_85'
chicago: Skórski, Maciej, Alexander Golovnev, and Krzysztof Z Pietrzak. “Condensed
Unpredictability ,” 9134:1046–57. Springer, 2015. https://doi.org/10.1007/978-3-662-47672-7_85.
ieee: 'M. Skórski, A. Golovnev, and K. Z. Pietrzak, “Condensed unpredictability
,” presented at the ICALP: Automata, Languages and Programming, Kyoto, Japan,
2015, vol. 9134, pp. 1046–1057.'
ista: 'Skórski M, Golovnev A, Pietrzak KZ. 2015. Condensed unpredictability . ICALP:
Automata, Languages and Programming, LNCS, vol. 9134, 1046–1057.'
mla: Skórski, Maciej, et al. Condensed Unpredictability . Vol. 9134, Springer,
2015, pp. 1046–57, doi:10.1007/978-3-662-47672-7_85.
short: M. Skórski, A. Golovnev, K.Z. Pietrzak, in:, Springer, 2015, pp. 1046–1057.
conference:
end_date: 2015-07-10
location: Kyoto, Japan
name: 'ICALP: Automata, Languages and Programming'
start_date: 2015-07-06
date_created: 2018-12-11T11:53:15Z
date_published: 2015-06-20T00:00:00Z
date_updated: 2021-01-12T06:52:15Z
day: '20'
ddc:
- '000'
- '005'
department:
- _id: KrPi
doi: 10.1007/978-3-662-47672-7_85
ec_funded: 1
file:
- access_level: open_access
checksum: e808c7eecb631336fc9f9bf2e8d4ecae
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:08:32Z
date_updated: 2020-07-14T12:45:08Z
file_id: '4693'
file_name: IST-2016-675-v1+1_384.pdf
file_size: 525503
relation: main_file
file_date_updated: 2020-07-14T12:45:08Z
has_accepted_license: '1'
intvolume: ' 9134'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
page: 1046 - 1057
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5500'
pubrep_id: '675'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'Condensed unpredictability '
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9134
year: '2015'
...
---
_id: '1651'
abstract:
- lang: eng
text: Cryptographic e-cash allows off-line electronic transactions between a bank,
users and merchants in a secure and anonymous fashion. A plethora of e-cash constructions
has been proposed in the literature; however, these traditional e-cash schemes
only allow coins to be transferred once between users and merchants. Ideally,
we would like users to be able to transfer coins between each other multiple times
before deposit, as happens with physical cash. “Transferable” e-cash schemes are
the solution to this problem. Unfortunately, the currently proposed schemes are
either completely impractical or do not achieve the desirable anonymity properties
without compromises, such as assuming the existence of a trusted “judge” who can
trace all coins and users in the system. This paper presents the first efficient
and fully anonymous transferable e-cash scheme without any trusted third parties.
We start by revising the security and anonymity properties of transferable e-cash
to capture issues that were previously overlooked. For our construction we use
the recently proposed malleable signatures by Chase et al. to allow the secure
and anonymous transfer of coins, combined with a new efficient double-spending
detection mechanism. Finally, we discuss an instantiation of our construction.
acknowledgement: Work done as an intern in Microsoft Research Redmond and as a student
at Brown University, where supported by NSF grant 0964379. Supported by the European
Research Council, ERC Starting Grant (259668-PSPC).
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Foteini
full_name: Baldimtsi, Foteini
last_name: Baldimtsi
- first_name: Melissa
full_name: Chase, Melissa
last_name: Chase
- first_name: Georg
full_name: Fuchsbauer, Georg
id: 46B4C3EE-F248-11E8-B48F-1D18A9856A87
last_name: Fuchsbauer
- first_name: Markulf
full_name: Kohlweiss, Markulf
last_name: Kohlweiss
citation:
ama: 'Baldimtsi F, Chase M, Fuchsbauer G, Kohlweiss M. Anonymous transferable e-cash.
In: Public-Key Cryptography - PKC 2015. Vol 9020. Springer; 2015:101-124.
doi:10.1007/978-3-662-46447-2_5'
apa: 'Baldimtsi, F., Chase, M., Fuchsbauer, G., & Kohlweiss, M. (2015). Anonymous
transferable e-cash. In Public-Key Cryptography - PKC 2015 (Vol. 9020,
pp. 101–124). Gaithersburg, MD, United States: Springer. https://doi.org/10.1007/978-3-662-46447-2_5'
chicago: Baldimtsi, Foteini, Melissa Chase, Georg Fuchsbauer, and Markulf Kohlweiss.
“Anonymous Transferable E-Cash.” In Public-Key Cryptography - PKC 2015,
9020:101–24. Springer, 2015. https://doi.org/10.1007/978-3-662-46447-2_5.
ieee: F. Baldimtsi, M. Chase, G. Fuchsbauer, and M. Kohlweiss, “Anonymous transferable
e-cash,” in Public-Key Cryptography - PKC 2015, Gaithersburg, MD, United
States, 2015, vol. 9020, pp. 101–124.
ista: 'Baldimtsi F, Chase M, Fuchsbauer G, Kohlweiss M. 2015. Anonymous transferable
e-cash. Public-Key Cryptography - PKC 2015. PKC: Public Key Crypography, LNCS,
vol. 9020, 101–124.'
mla: Baldimtsi, Foteini, et al. “Anonymous Transferable E-Cash.” Public-Key Cryptography
- PKC 2015, vol. 9020, Springer, 2015, pp. 101–24, doi:10.1007/978-3-662-46447-2_5.
short: F. Baldimtsi, M. Chase, G. Fuchsbauer, M. Kohlweiss, in:, Public-Key Cryptography
- PKC 2015, Springer, 2015, pp. 101–124.
conference:
end_date: 2015-04-01
location: Gaithersburg, MD, United States
name: 'PKC: Public Key Crypography'
start_date: 2015-03-30
date_created: 2018-12-11T11:53:15Z
date_published: 2015-03-17T00:00:00Z
date_updated: 2022-05-23T10:08:37Z
day: '17'
department:
- _id: KrPi
doi: 10.1007/978-3-662-46447-2_5
ec_funded: 1
intvolume: ' 9020'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1007/978-3-662-46447-2_5
month: '03'
oa: 1
oa_version: Published Version
page: 101 - 124
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: Public-Key Cryptography - PKC 2015
publication_identifier:
isbn:
- 978-3-662-46446-5
publication_status: published
publisher: Springer
publist_id: '5499'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Anonymous transferable e-cash
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9020
year: '2015'
...
---
_id: '1652'
abstract:
- lang: eng
text: We develop new theoretical tools for proving lower-bounds on the (amortized)
complexity of certain functions in models of parallel computation. We apply the
tools to construct a class of functions with high amortized memory complexity
in the parallel Random Oracle Model (pROM); a variant of the standard ROM allowing
for batches of simultaneous queries. In particular we obtain a new, more robust,
type of Memory-Hard Functions (MHF); a security primitive which has recently been
gaining acceptance in practice as an effective means of countering brute-force
attacks on security relevant functions. Along the way we also demonstrate an important
shortcoming of previous definitions of MHFs and give a new definition addressing
the problem. The tools we develop represent an adaptation of the powerful pebbling
paradigm (initially introduced by Hewitt and Paterson [HP70] and Cook [Coo73])
to a simple and intuitive parallel setting. We define a simple pebbling game Gp
over graphs which aims to abstract parallel computation in an intuitive way. As
a conceptual contribution we define a measure of pebbling complexity for graphs
called cumulative complexity (CC) and show how it overcomes a crucial shortcoming
(in the parallel setting) exhibited by more traditional complexity measures used
in the past. As a main technical contribution we give an explicit construction
of a constant in-degree family of graphs whose CC in Gp approaches maximality
to within a polylogarithmic factor for any graph of equal size (analogous to the
graphs of Tarjan et. al. [PTC76, LT82] for sequential pebbling games). Finally,
for a given graph G and related function fG, we derive a lower-bound on the amortized
memory complexity of fG in the pROM in terms of the CC of G in the game Gp.
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Vladimir
full_name: Serbinenko, Vladimir
last_name: Serbinenko
citation:
ama: 'Alwen JF, Serbinenko V. High parallel complexity graphs and memory-hard functions.
In: Proceedings of the 47th Annual ACM Symposium on Theory of Computing.
ACM; 2015:595-603. doi:10.1145/2746539.2746622'
apa: 'Alwen, J. F., & Serbinenko, V. (2015). High parallel complexity graphs
and memory-hard functions. In Proceedings of the 47th annual ACM symposium
on Theory of computing (pp. 595–603). Portland, OR, United States: ACM. https://doi.org/10.1145/2746539.2746622'
chicago: Alwen, Joel F, and Vladimir Serbinenko. “High Parallel Complexity Graphs
and Memory-Hard Functions.” In Proceedings of the 47th Annual ACM Symposium
on Theory of Computing, 595–603. ACM, 2015. https://doi.org/10.1145/2746539.2746622.
ieee: J. F. Alwen and V. Serbinenko, “High parallel complexity graphs and memory-hard
functions,” in Proceedings of the 47th annual ACM symposium on Theory of computing,
Portland, OR, United States, 2015, pp. 595–603.
ista: 'Alwen JF, Serbinenko V. 2015. High parallel complexity graphs and memory-hard
functions. Proceedings of the 47th annual ACM symposium on Theory of computing.
STOC: Symposium on the Theory of Computing, 595–603.'
mla: Alwen, Joel F., and Vladimir Serbinenko. “High Parallel Complexity Graphs and
Memory-Hard Functions.” Proceedings of the 47th Annual ACM Symposium on Theory
of Computing, ACM, 2015, pp. 595–603, doi:10.1145/2746539.2746622.
short: J.F. Alwen, V. Serbinenko, in:, Proceedings of the 47th Annual ACM Symposium
on Theory of Computing, ACM, 2015, pp. 595–603.
conference:
end_date: 2015-06-17
location: Portland, OR, United States
name: 'STOC: Symposium on the Theory of Computing'
start_date: 2015-06-14
date_created: 2018-12-11T11:53:16Z
date_published: 2015-06-01T00:00:00Z
date_updated: 2021-01-12T06:52:16Z
day: '01'
department:
- _id: KrPi
doi: 10.1145/2746539.2746622
ec_funded: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://eprint.iacr.org/2014/238
month: '06'
oa: 1
oa_version: Submitted Version
page: 595 - 603
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: Proceedings of the 47th annual ACM symposium on Theory of computing
publication_status: published
publisher: ACM
publist_id: '5498'
quality_controlled: '1'
scopus_import: 1
status: public
title: High parallel complexity graphs and memory-hard functions
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2015'
...
---
_id: '1672'
abstract:
- lang: eng
text: Composable notions of incoercibility aim to forbid a coercer from using anything
beyond the coerced parties’ inputs and outputs to catch them when they try to
deceive him. Existing definitions are restricted to weak coercion types, and/or
are not universally composable. Furthermore, they often make too strong assumptions
on the knowledge of coerced parties—e.g., they assume they known the identities
and/or the strategies of other coerced parties, or those of corrupted parties—
which makes them unsuitable for applications of incoercibility such as e-voting,
where colluding adversarial parties may attempt to coerce honest voters, e.g.,
by offering them money for a promised vote, and use their own view to check that
the voter keeps his end of the bargain. In this work we put forward the first
universally composable notion of incoercible multi-party computation, which satisfies
the above intuition and does not assume collusions among coerced parties or knowledge
of the corrupted set. We define natural notions of UC incoercibility corresponding
to standard coercion-types, i.e., receipt-freeness and resistance to full-active
coercion. Importantly, our suggested notion has the unique property that it builds
on top of the well studied UC framework by Canetti instead of modifying it. This
guarantees backwards compatibility, and allows us to inherit results from the
rich UC literature. We then present MPC protocols which realize our notions of
UC incoercibility given access to an arguably minimal setup—namely honestly generate
tamper-proof hardware performing a very simple cryptographic operation—e.g., a
smart card. This is, to our knowledge, the first proposed construction of an MPC
protocol (for more than two parties) that is incoercibly secure and universally
composable, and therefore the first construction of a universally composable receipt-free
e-voting protocol.
acknowledgement: Joël Alwen was supported by the ERC starting grant (259668-PSPC).
Rafail Ostrovsky was supported in part by NSF grants 09165174, 1065276, 1118126
and 1136174, US-Israel BSF grant 2008411, OKAWA Foundation Research Award, IBM Faculty
Research Award, Xerox Faculty Research Award, B. John Garrick Foundation Award,
Teradata Research Award, Lockheed-Martin Corporation Research Award, and the Defense
Advanced Research Projects Agency through the U.S. Office of Naval Research under
Contract N00014 -11 -1-0392. The views expressed are those of the author and do
not reflect the official policy or position of the Department of Defense or the
U.S. Government. Vassilis Zikas was supported in part by the Swiss National Science
Foundation (SNF) via the Ambizione grant PZ00P-2142549.
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Joel F
full_name: Alwen, Joel F
id: 2A8DFA8C-F248-11E8-B48F-1D18A9856A87
last_name: Alwen
- first_name: Rafail
full_name: Ostrovsky, Rafail
last_name: Ostrovsky
- first_name: Hongsheng
full_name: Zhou, Hongsheng
last_name: Zhou
- first_name: Vassilis
full_name: Zikas, Vassilis
last_name: Zikas
citation:
ama: 'Alwen JF, Ostrovsky R, Zhou H, Zikas V. Incoercible multi-party computation
and universally composable receipt-free voting. In: Advances in Cryptology
- CRYPTO 2015. Vol 9216. Lecture Notes in Computer Science. Springer; 2015:763-780.
doi:10.1007/978-3-662-48000-7_37'
apa: 'Alwen, J. F., Ostrovsky, R., Zhou, H., & Zikas, V. (2015). Incoercible
multi-party computation and universally composable receipt-free voting. In Advances
in Cryptology - CRYPTO 2015 (Vol. 9216, pp. 763–780). Santa Barbara, CA, United
States: Springer. https://doi.org/10.1007/978-3-662-48000-7_37'
chicago: Alwen, Joel F, Rafail Ostrovsky, Hongsheng Zhou, and Vassilis Zikas. “Incoercible
Multi-Party Computation and Universally Composable Receipt-Free Voting.” In Advances
in Cryptology - CRYPTO 2015, 9216:763–80. Lecture Notes in Computer Science.
Springer, 2015. https://doi.org/10.1007/978-3-662-48000-7_37.
ieee: J. F. Alwen, R. Ostrovsky, H. Zhou, and V. Zikas, “Incoercible multi-party
computation and universally composable receipt-free voting,” in Advances in
Cryptology - CRYPTO 2015, Santa Barbara, CA, United States, 2015, vol. 9216,
pp. 763–780.
ista: 'Alwen JF, Ostrovsky R, Zhou H, Zikas V. 2015. Incoercible multi-party computation
and universally composable receipt-free voting. Advances in Cryptology - CRYPTO
2015. CRYPTO: International Cryptology ConferenceLecture Notes in Computer Science,
LNCS, vol. 9216, 763–780.'
mla: Alwen, Joel F., et al. “Incoercible Multi-Party Computation and Universally
Composable Receipt-Free Voting.” Advances in Cryptology - CRYPTO 2015,
vol. 9216, Springer, 2015, pp. 763–80, doi:10.1007/978-3-662-48000-7_37.
short: J.F. Alwen, R. Ostrovsky, H. Zhou, V. Zikas, in:, Advances in Cryptology
- CRYPTO 2015, Springer, 2015, pp. 763–780.
conference:
end_date: 2015-08-20
location: Santa Barbara, CA, United States
name: 'CRYPTO: International Cryptology Conference'
start_date: 2015-08-16
date_created: 2018-12-11T11:53:23Z
date_published: 2015-08-01T00:00:00Z
date_updated: 2022-06-07T09:51:55Z
day: '01'
ddc:
- '000'
department:
- _id: KrPi
doi: 10.1007/978-3-662-48000-7_37
ec_funded: 1
file:
- access_level: open_access
checksum: 5b6649e80d1f781a8910f7cce6427f78
content_type: application/pdf
creator: dernst
date_created: 2020-05-15T08:55:29Z
date_updated: 2020-07-14T12:45:11Z
file_id: '7853'
file_name: 2015_CRYPTO_Alwen.pdf
file_size: 397363
relation: main_file
file_date_updated: 2020-07-14T12:45:11Z
has_accepted_license: '1'
intvolume: ' 9216'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Submitted Version
page: 763 - 780
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication: Advances in Cryptology - CRYPTO 2015
publication_identifier:
eisbn:
- 978-3-662-48000-7
isbn:
- 978-3-662-47999-5
publication_status: published
publisher: Springer
publist_id: '5476'
quality_controlled: '1'
scopus_import: '1'
series_title: Lecture Notes in Computer Science
status: public
title: Incoercible multi-party computation and universally composable receipt-free
voting
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9216
year: '2015'
...
---
_id: '1669'
abstract:
- lang: eng
text: Computational notions of entropy (a.k.a. pseudoentropy) have found many applications,
including leakage-resilient cryptography, deterministic encryption or memory delegation.
The most important tools to argue about pseudoentropy are chain rules, which quantify
by how much (in terms of quantity and quality) the pseudoentropy of a given random
variable X decreases when conditioned on some other variable Z (think for example
of X as a secret key and Z as information leaked by a side-channel). In this paper
we give a very simple and modular proof of the chain rule for HILL pseudoentropy,
improving best known parameters. Our version allows for increasing the acceptable
length of leakage in applications up to a constant factor compared to the best
previous bounds. As a contribution of independent interest, we provide a comprehensive
study of all known versions of the chain rule, comparing their worst-case strength
and limitations.
alternative_title:
- LNCS
author:
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Maciej
full_name: Skórski, Maciej
last_name: Skórski
citation:
ama: Pietrzak KZ, Skórski M. The chain rule for HILL pseudoentropy, revisited. 2015;9230:81-98.
doi:10.1007/978-3-319-22174-8_5
apa: 'Pietrzak, K. Z., & Skórski, M. (2015). The chain rule for HILL pseudoentropy,
revisited. Presented at the LATINCRYPT: Cryptology and Information Security in
Latin America, Guadalajara, Mexico: Springer. https://doi.org/10.1007/978-3-319-22174-8_5'
chicago: Pietrzak, Krzysztof Z, and Maciej Skórski. “The Chain Rule for HILL Pseudoentropy,
Revisited.” Lecture Notes in Computer Science. Springer, 2015. https://doi.org/10.1007/978-3-319-22174-8_5.
ieee: K. Z. Pietrzak and M. Skórski, “The chain rule for HILL pseudoentropy, revisited,”
vol. 9230. Springer, pp. 81–98, 2015.
ista: Pietrzak KZ, Skórski M. 2015. The chain rule for HILL pseudoentropy, revisited.
9230, 81–98.
mla: Pietrzak, Krzysztof Z., and Maciej Skórski. The Chain Rule for HILL Pseudoentropy,
Revisited. Vol. 9230, Springer, 2015, pp. 81–98, doi:10.1007/978-3-319-22174-8_5.
short: K.Z. Pietrzak, M. Skórski, 9230 (2015) 81–98.
conference:
end_date: 2015-08-26
location: Guadalajara, Mexico
name: 'LATINCRYPT: Cryptology and Information Security in Latin America'
start_date: 2015-08-23
date_created: 2018-12-11T11:53:22Z
date_published: 2015-08-15T00:00:00Z
date_updated: 2021-01-12T06:52:24Z
day: '15'
ddc:
- '005'
department:
- _id: KrPi
doi: 10.1007/978-3-319-22174-8_5
ec_funded: 1
file:
- access_level: open_access
checksum: 8cd4215b83efba720e8cf27c23ff4781
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:18:29Z
date_updated: 2020-07-14T12:45:11Z
file_id: '5351'
file_name: IST-2016-669-v1+1_599.pdf
file_size: 443340
relation: main_file
file_date_updated: 2020-07-14T12:45:11Z
has_accepted_license: '1'
intvolume: ' 9230'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Submitted Version
page: 81 - 98
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5480'
pubrep_id: '669'
quality_controlled: '1'
scopus_import: 1
series_title: Lecture Notes in Computer Science
status: public
title: The chain rule for HILL pseudoentropy, revisited
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9230
year: '2015'
...
---
_id: '1671'
abstract:
- lang: eng
text: This paper studies the concrete security of PRFs and MACs obtained by keying
hash functions based on the sponge paradigm. One such hash function is KECCAK,
selected as NIST’s new SHA-3 standard. In contrast to other approaches like HMAC,
the exact security of keyed sponges is not well understood. Indeed, recent security
analyses delivered concrete security bounds which are far from existing attacks.
This paper aims to close this gap. We prove (nearly) exact bounds on the concrete
PRF security of keyed sponges using a random permutation. These bounds are tight
for the most relevant ranges of parameters, i.e., for messages of length (roughly)
l ≤ min{2n/4, 2r} blocks, where n is the state size and r is the desired output
length; and for l ≤ q queries (to the construction or the underlying permutation).
Moreover, we also improve standard-model bounds. As an intermediate step of independent
interest, we prove tight bounds on the PRF security of the truncated CBC-MAC construction,
which operates as plain CBC-MAC, but only returns a prefix of the output.
alternative_title:
- LNCS
author:
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Krzysztof Z
full_name: Pietrzak, Krzysztof Z
id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
last_name: Pietrzak
orcid: 0000-0002-9139-1654
- first_name: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: 'Gazi P, Pietrzak KZ, Tessaro S. The exact PRF security of truncation: Tight
bounds for keyed sponges and truncated CBC. In: Vol 9215. Springer; 2015:368-387.
doi:10.1007/978-3-662-47989-6_18'
apa: 'Gazi, P., Pietrzak, K. Z., & Tessaro, S. (2015). The exact PRF security
of truncation: Tight bounds for keyed sponges and truncated CBC (Vol. 9215, pp.
368–387). Presented at the CRYPTO: International Cryptology Conference, Santa
Barbara, CA, United States: Springer. https://doi.org/10.1007/978-3-662-47989-6_18'
chicago: 'Gazi, Peter, Krzysztof Z Pietrzak, and Stefano Tessaro. “The Exact PRF
Security of Truncation: Tight Bounds for Keyed Sponges and Truncated CBC,” 9215:368–87.
Springer, 2015. https://doi.org/10.1007/978-3-662-47989-6_18.'
ieee: 'P. Gazi, K. Z. Pietrzak, and S. Tessaro, “The exact PRF security of truncation:
Tight bounds for keyed sponges and truncated CBC,” presented at the CRYPTO: International
Cryptology Conference, Santa Barbara, CA, United States, 2015, vol. 9215, pp.
368–387.'
ista: 'Gazi P, Pietrzak KZ, Tessaro S. 2015. The exact PRF security of truncation:
Tight bounds for keyed sponges and truncated CBC. CRYPTO: International Cryptology
Conference, LNCS, vol. 9215, 368–387.'
mla: 'Gazi, Peter, et al. The Exact PRF Security of Truncation: Tight Bounds
for Keyed Sponges and Truncated CBC. Vol. 9215, Springer, 2015, pp. 368–87,
doi:10.1007/978-3-662-47989-6_18.'
short: P. Gazi, K.Z. Pietrzak, S. Tessaro, in:, Springer, 2015, pp. 368–387.
conference:
end_date: 2015-08-20
location: Santa Barbara, CA, United States
name: 'CRYPTO: International Cryptology Conference'
start_date: 2015-08-16
date_created: 2018-12-11T11:53:23Z
date_published: 2015-08-01T00:00:00Z
date_updated: 2021-01-12T06:52:25Z
day: '01'
ddc:
- '004'
- '005'
department:
- _id: KrPi
doi: 10.1007/978-3-662-47989-6_18
ec_funded: 1
file:
- access_level: open_access
checksum: 17d854227b3b753fd34f5d29e5b5a32e
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:10:38Z
date_updated: 2020-07-14T12:45:11Z
file_id: '4827'
file_name: IST-2016-673-v1+1_053.pdf
file_size: 592296
relation: main_file
file_date_updated: 2020-07-14T12:45:11Z
has_accepted_license: '1'
intvolume: ' 9215'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Submitted Version
page: 368 - 387
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5478'
pubrep_id: '673'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'The exact PRF security of truncation: Tight bounds for keyed sponges and truncated
CBC'
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9215
year: '2015'
...
---
_id: '1668'
abstract:
- lang: eng
text: "We revisit the security (as a pseudorandom permutation) of cascading-based
constructions for block-cipher key-length extension. Previous works typically
considered the extreme case where the adversary is given the entire codebook of
the construction, the only complexity measure being the number qe of queries to
the underlying ideal block cipher, representing adversary’s secret-key-independent
computation. Here, we initiate a systematic study of the more natural case of
an adversary restricted to adaptively learning a number qc of plaintext/ciphertext
pairs that is less than the entire codebook. For any such qc, we aim to determine
the highest number of block-cipher queries qe the adversary can issue without
being able to successfully distinguish the construction (under a secret key) from
a random permutation.\r\nMore concretely, we show the following results for key-length
extension schemes using a block cipher with n-bit blocks and κ-bit keys:\r\nPlain
cascades of length ℓ=2r+1 are secure whenever qcqre≪2r(κ+n), qc≪2κ and qe≪22κ.
The bound for r=1 also applies to two-key triple encryption (as used within Triple
DES).\r\nThe r-round XOR-cascade is secure as long as qcqre≪2r(κ+n), matching
an attack by Gaži (CRYPTO 2013).\r\nWe fully characterize the security of Gaži
and Tessaro’s two-call "
alternative_title:
- LNCS
author:
- first_name: Peter
full_name: Gazi, Peter
id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87
last_name: Gazi
- first_name: Jooyoung
full_name: Lee, Jooyoung
last_name: Lee
- first_name: Yannick
full_name: Seurin, Yannick
last_name: Seurin
- first_name: John
full_name: Steinberger, John
last_name: Steinberger
- first_name: Stefano
full_name: Tessaro, Stefano
last_name: Tessaro
citation:
ama: 'Gazi P, Lee J, Seurin Y, Steinberger J, Tessaro S. Relaxing full-codebook
security: A refined analysis of key-length extension schemes. 2015;9054:319-341.
doi:10.1007/978-3-662-48116-5_16'
apa: 'Gazi, P., Lee, J., Seurin, Y., Steinberger, J., & Tessaro, S. (2015).
Relaxing full-codebook security: A refined analysis of key-length extension schemes.
Presented at the FSE: Fast Software Encryption, Istanbul, Turkey: Springer. https://doi.org/10.1007/978-3-662-48116-5_16'
chicago: 'Gazi, Peter, Jooyoung Lee, Yannick Seurin, John Steinberger, and Stefano
Tessaro. “Relaxing Full-Codebook Security: A Refined Analysis of Key-Length Extension
Schemes.” Lecture Notes in Computer Science. Springer, 2015. https://doi.org/10.1007/978-3-662-48116-5_16.'
ieee: 'P. Gazi, J. Lee, Y. Seurin, J. Steinberger, and S. Tessaro, “Relaxing full-codebook
security: A refined analysis of key-length extension schemes,” vol. 9054. Springer,
pp. 319–341, 2015.'
ista: 'Gazi P, Lee J, Seurin Y, Steinberger J, Tessaro S. 2015. Relaxing full-codebook
security: A refined analysis of key-length extension schemes. 9054, 319–341.'
mla: 'Gazi, Peter, et al. Relaxing Full-Codebook Security: A Refined Analysis
of Key-Length Extension Schemes. Vol. 9054, Springer, 2015, pp. 319–41, doi:10.1007/978-3-662-48116-5_16.'
short: P. Gazi, J. Lee, Y. Seurin, J. Steinberger, S. Tessaro, 9054 (2015) 319–341.
conference:
end_date: 2015-03-11
location: Istanbul, Turkey
name: 'FSE: Fast Software Encryption'
start_date: 2015-03-08
date_created: 2018-12-11T11:53:22Z
date_published: 2015-08-12T00:00:00Z
date_updated: 2020-08-11T10:09:26Z
day: '12'
department:
- _id: KrPi
doi: 10.1007/978-3-662-48116-5_16
ec_funded: 1
intvolume: ' 9054'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://eprint.iacr.org/2015/397
month: '08'
oa: 1
oa_version: Submitted Version
page: 319 - 341
project:
- _id: 258C570E-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '259668'
name: Provable Security for Physical Cryptography
publication_status: published
publisher: Springer
publist_id: '5481'
quality_controlled: '1'
scopus_import: 1
series_title: Lecture Notes in Computer Science
status: public
title: 'Relaxing full-codebook security: A refined analysis of key-length extension
schemes'
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9054
year: '2015'
...