md5sum is a computer program that calculates and verifies 128-bit MD5 hashes, as described in RFC 1321.
The md5sum program is included in most Unix-like operating systems or compatibility layers such as Cygwin.
The original C code was written by Ulrich Drepper and extracted from a 2001 release of glibc.
File contains hash and filename pairs: Please note: md5sum is specific to systems that use GNU coreutils or a clone such as BusyBox.
Additionally, FreeBSD offers the "SKEIN" family of message digests.