MD5 - Cryptographic Library for Lua
Copyright 2003 PUC-Rio
http://www.keplerproject.org/md5

MD5 offers basic cryptographic facilities for Lua 5.1: a hash (digest)
function, a pair crypt/decrypt based on MD5 and CFB, and a pair crypt/decrypt based
on DES with 56-bit keys.

MD5 current version is 1.1.2.

This version is copy from https://github.com/keplerproject/md5