sha is a simple program that hashes files. It uses the National
Institute of Standards and Technology's Secure Hash Algorithm.
It can use SHA-1, SHA-256, SHA-384, or SHA-512, which generate
respectively, hashes of 160, 256, 384, or 512 bits. sha can be
used in scripts to do, for example, file integrity checking.

WWW: http://www.saddi.com/software/sha/