The scrypt key derivation function was originally developed for use in the
Tarsnap online backup system and is designed to be far more secure against
hardware brute-force attacks than alternative functions such as PBKDF2 or
bcrypt.

This simple password-based encryption utility is available as a demonstration
of the scrypt key derivation function. On modern hardware and with default
parameters, the cost of cracking the password on a file encrypted by scrypt
enc is approximately 100 billion times more than the cost of cracking the same
password on a file encrypted by openssl enc; this means that a five-character
password using scrypt is stronger than a ten-character password using openssl.
