SB-SHA1 Checksum Calculator is a tool to calculate and compare the SHA1 checksum of files. The SHA1 is a 160-bit hash function which resembles the earlier MD5 algorithm. This was designed by the National Security Agency (NSA) to be part of the Digital Signature Algorithm. Features Calculate SHA1 checksum of a file. Compare SHA1 checksum of two files. Copy SHA1 hash to Windows clipboard. Compare value from the clipboard with SHA1 checksum of a file. It is free.