The MD5 message-digest algorithm created in 1991 by Professor Ronald Rivest that is a widely used cryptographic hash function producing a 128-bit hash values (digital signatures). It is intended for use with 32 bit machines and is safer than the MD4 algorithm, which has been broken. MD5 is a one-way hash function, meaning that it takes a message and converts it into a fixed string of digits, also called a message digest.