Message Digest hash
md5 x md5[x]
x is a string, returns as a bytestream its MD5 (Message-Digest algorithm 5) hash.
q)md5 "this is a not so secret message" 0x6cf192c1938b79012c323fa30e62787e
MD5 is a widely used, Internet standard (RFC 1321), hash function that computes a 128-bit hash, commonly used to check the integrity of files. It is not recommended for serious cryptographic protection, for which strong hashes should be used.