An MD5 hash is created by taking a string of an any length and encoding it into a 128-bit fingerprint.
Encoding the same string using the MD5 algorithm will always result in the same 128-bit hash output.
MD5 hashes are commonly used with smaller strings when storing passwords,
credit card numbers or other sensitive data in databases such as the popular MySQL.
An MD5 hash is NOT encryption. It is simply a fingerprint of the given input.
However, it is a one-way transaction and as such it is almost impossible to reverse engineer an MD5 hash to retrieve the original string.