---
res:
bibo_abstract:
- "A proof system is a protocol between a prover and a verifier over a common input
in which an honest prover convinces the verifier of the validity of true statements.
Motivated by the success of decentralized cryptocurrencies, exemplified by Bitcoin,
the focus of this thesis will be on proof systems which found applications in
some sustainable alternatives to Bitcoin, such as the Spacemint and Chia cryptocurrencies.
In particular, we focus on proofs of space and proofs of sequential work.\r\nProofs
of space (PoSpace) were suggested as more ecological, economical, and egalitarian
alternative to the energy-wasteful proof-of-work mining of Bitcoin. However, the
state-of-the-art constructions of PoSpace are based on sophisticated graph pebbling
lower bounds, and are therefore complex. Moreover, when these PoSpace are used
in cryptocurrencies like Spacemint, miners can only start mining after ensuring
that a commitment to their space is already added in a special transaction to
the blockchain. Proofs of sequential work (PoSW) are proof systems in which a
prover, upon receiving a statement x and a time parameter T, computes a proof
which convinces the verifier that T time units had passed since x was received.
Whereas Spacemint assumes synchrony to retain some interesting Bitcoin dynamics,
Chia requires PoSW with unique proofs, i.e., PoSW in which it is hard to come
up with more than one accepting proof for any true statement. In this thesis we
construct simple and practically-efficient PoSpace and PoSW. When using our PoSpace
in cryptocurrencies, miners can start mining on the fly, like in Bitcoin, and
unlike current constructions of PoSW, which either achieve efficient verification
of sequential work, or faster-than-recomputing verification of correctness of
proofs, but not both at the same time, ours achieve the best of these two worlds.@eng"
bibo_authorlist:
- foaf_Person:
foaf_givenName: Hamza M
foaf_name: Abusalah, Hamza M
foaf_surname: Abusalah
foaf_workInfoHomepage: http://www.librecat.org/personId=40297222-F248-11E8-B48F-1D18A9856A87
bibo_doi: 10.15479/AT:ISTA:TH_1046
dct_date: 2018^xs_gYear
dct_language: eng
dct_publisher: IST Austria@
dct_title: Proof systems for sustainable decentralized cryptocurrencies@
...