Message Recovery and Pseudo-preimage Attacks on the Compression Function of Hamsi-256

Hamsi is one of the second round candidates of the SHA-3 competition In this study, we present non-random differential properties for the compression function of Hamsi-256 Based on these properties, we first demonstrate a distinguishing attack that requires a few evaluations of the compression function Then, we present a message recovery attack with a complexity of 210 48 compression function evaluations Also, we present a pseudo-preimage attack for the compression function with complexity 2(254 25)