Non-linear Reduced Round Attacks against SHA-2 Hash Family

Most of the attacks against (reduced) SHA-2 family in literature have used local collisions which are valid for linearized version of SHA-2 hash functions. Recently, at FSE ’08, an attack against reduced round SHA-256 was presented by Nikoli´c and Biryukov which used a local collision which is valid for the actual SHA-256 function. It is a 9-step local collision which starts by introducing a modular difference of 1 in the two messages. It succeeds with probability roughly 1/3. We build on the work of Nikoli´c and Biryukov and provide a generalized nonlinear local collision which accepts an arbitrary initial message difference. This

• Type: Conference
• Year: 2008
• Where: ACISP
• Authors: Somitra Kumar Sanadhya, Palash Sarkar
• Keywords: 9-step Local Collision, ACISP 2008, Local Collision, Security Privacy, SHA-2 Hash Functions