Introduction to some resistance of hash functions Description of the Biham-Chen attack Cryptanalysis of hash functions in encryption mode Pseudo-collision attack on MD5 Pseudo-collision attack on a SHA-256 variant Observation on SHA-256 Conclusions

Biham and Chen proposed an attack on SHA-0 at Crypt 2004. In this paper, we apply the Biham-Chen attack to analyze SHAlike hash functions regarding pseudo-collision resistance and pseudorandomness. We present a scenario about how to attack SHA-like hash functions applying the Biham and Chen attack. Using this scenario, we present a differential attack on the MD5 hash function and a differential attack on a variant of SHA-256 hash function. We also study certain several rounds’ property of the real SHA-256 function.