International Association for Cryptologic Research
In this paper, the authors analyze the security of RIPEMD-128 against collision attacks. The ISO/IEC standard RIPEMD-128 was proposed 15 years ago and may be used as a drop-in replacement for 128-bit hash functions like MD5. Only few results have been published for RIPEMD-128, the best being a pre-image attack for the first 33 steps of the hash function with complexity 2124.5. In this paper, they provide a new assessment of the security margin of RIPEMD-128 by showing attacks on up to 48 (out of 64) steps of the hash function.