||SQL Server Tips by Gama and Naughter
MD4, MD5 and SHA Hash Algorithm
MD4 is a hash function designed by Ron Rivest and published in RFC
1186 in 1990. The MD4 algorithm produces a hash value which is 128
bits or 16 bytes in size. After the algorithm was first introduced
it was successfully crypto analyzed. Details of the XP
implementation for MD4 is described later in the section on MD5
MD5 Hash Algorithm
Ron Rivest developed MD5 in response to the problems discovered in
MD4. As with MD4, it produces a 128-bit hash value. It is described
in RFC 1321.
SHA Hash Algorithm
NIST, along with the National Security Agency (NSA), designed the
Secure Hash Algorithm for use with the Digital Signal Standard. The
standard SHA1 algorithm produces a 160-bit or 20-byte hash value.
Other versions of SHA allow for even longer key lengths namely
SHA-256, SHA-384 and SHA-512. The increased size of the SHA1 hash
value compared to MD5 means that the chance of collision between
hash values is much reduced. The longer key length versions of SHA
are only available on Windows 2003.
The above book excerpt is from:
Turbocharge Database Performance with C++ External Procedures
Joseph Gama, P. J. Naughter