Improved Analysis of ECHO-256

Jérémy Jean (1) , María Naya-Plasencia (2) , Martin Schläffer (3)

1 CASCADE - Construction and Analysis of Systems for Confidentiality and Authenticity of Data and Entities
2 FHNW - Fachhochschule Nordwestschweiz [Windisch]
3 IAIK - Institute of Applied Information Processing and Communications [Graz]

ECHO-256 is a second-round candidate of the SHA-3 competition. It is an AES-based hash function that has attracted a lot of interest and analysis. Up to now, the best known attacks were a distinguisher on the full internal permutation and a collision on four rounds of its compression function. The latter was the best known analysis on the compression function as well as the one on the largest number of rounds so far. In this paper, we extend the compression function results to get a distinguisher on 7 out of 8 rounds using rebound techniques. We also present the first 5-round collision attack on the ECHO-256 hash function.

Mots clés: distinguisher; collision attack; rebound attack; cryptanalysis; hash function

Domaines: Cryptographie et sécurité [cs.CR]

Jérémy Jean, María Naya-Plasencia, Martin Schläffer. Improved Analysis of ECHO-256. SAC 2011 - 18th International Workshop Selected Areas in Cryptography, Aug 2011, Toronto, Canada. pp.19-36, ⟨10.1007/978-3-642-28496-0_2⟩. ⟨hal-01110465⟩