Searching for Messages Conforming to Arbitrary Sets of Conditions in SHA-256

摘要

Recent progress in hash functions analysis has led to collisions on reduced versions of SHA-256. As in other hash functions, differential collision search methods of SHA-256 can be described by means of conditions on and between state and message bits. We describe a tool for efficient automatic searching of message pairs conforming to useful sets of conditions, i. e. stemming from (interleaved) local collisions. We not only considerably improve upon previous work [7], but also show the extendability of our approach to larger sets of conditions.rnFurthermore, we present the performance results of an actual implementation and pose an open problem in this context.