Message Digest Algorithms

Both the MD5 and SHA (Secure Hash Algorithm) are message
digest algorithms. Both MD5 and SHA are well known, one-way hash
algorithms. A one-way hash algorithm takes a message and converts it
into a fixed string of digits, which is referred to as a message digest
or hash value.

MD5 is a high-speed, 128-bit hash; it is intended for use with 32-bit
machines. SHA offers more security by using a 160-bit hash, but is
slower than MD5.