CryptoDB
Emilia Käsper
Affiliation: Google
Publications
Year
Venue
Title
2010
EPRINT
Distinguishers for the Compression Function and Output Transformation of Hamsi-256
Abstract
Hamsi is one of 14 remaining candidates in NIST's Hash Competition for the future hash standard SHA-3. Until now, little analysis has been published on its resistance to differential cryptanalysis, the main technique used to attack hash functions. We present a study of Hamsi's resistance to differential and higher-order differential cryptanalysis, with focus on the 256-bit version of Hamsi. Our main results are efficient distinguishers and near-collisions for its full (3-round) compression function, and distinguishers for its full (6-round) finalization function, indicating that Hamsi's building blocks do not behave ideally.
2006
EPRINT
Black-Box Knowledge Extraction Revisited: Universal Approach with Precise Bounds
Abstract
Rewinding techniques form the essence of many security reductions including proofs for identification and signature schemes. We propose a simple and modular approach for the construction of such proofs.
Straightforward applications of our central result include, but are not limited to, the security of identification schemes, generic signatures and ring signatures. These results are well known, however, we generalise them in such a way that our technique can be used off-the-shelf for future applications. We note that less is more: as a side-effect of our less complex analysis, all our proofs are more precise; for example, we get a new proof of the forking lemma that is $2^{15}$ times more precise than the original result by Pointcheval and Stern. Finally, we give the first precise security analysis of Blum's coin flipping protocol with $k$-bit strings, as yet another example of the strength of our results.
Program Committees
- CHES 2018
Coauthors
- Jean-Philippe Aumasson (1)
- Sebastian Faust (1)
- Lars R. Knudsen (1)
- Sven Laur (1)
- Helger Lipmaa (1)
- Stefan Lucks (1)
- Krystian Matusiewicz (1)
- Rune Odegaard (1)
- Thomas Peyrin (1)
- Martin Schläffer (1)
- Peter Schwabe (1)