International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Tertuliano C. de Souza Neto

Publications

Year
Venue
Title
2021
EUROCRYPT
Improved Linear Approximations to ARX Ciphers and Attacks Against ChaCha
Murilo Coutinho Silva Tertuliano C. de Souza Neto
In this paper, we present a new technique which can be used to find better linear approximations in ARX ciphers. Using this technique, we present the first explicitly derived linear approximations for 3 and 4 rounds of ChaCha and, as a consequence, it enables us to improve the recent attacks against ChaCha. Additionally, we present new differentials for 3 and 3.5 rounds of ChaCha that, when combined with the proposed technique, lead to further improvement in the complexity of the Differential-Linear attacks against ChaCha.

Coauthors

Murilo Coutinho Silva (1)