---
_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'
...