May 26, 2018
Library and command line tool to detect SHA-1 collisions
This library and command line tool were designed as near drop-in replacements for common SHA-1 libraries and sha1sum. They will compute the SHA-1 hash of any given file and additionally will detect cryptanalytic collision attacks against SHA-1 present in each file. It is very fast and takes less than twice the amount of time as regular SHA-1.
There are two programs sha1dcsum and sha1dcsum_partialcoll. The first program, sha1dcsum, will detect and warn for files that were generated with a cryptanalytic SHA-1 collision attack like the one documented at https//shattered.io/. The second program, sha1dcsum_partialcoll, will detect and warn for files that were generated with a cryptanalytic collision attack against reduced- round SHA-1 of which there are a few examples so far.