Come And Go Encryption (CAG) is a simple program
to encrypt files with a special key. This key is
a random garbage file, and it is XOR-ed with the
file to render it unusable by normal methods. It
uses the principle of the one-time pad, but it is
not unbreakable. It can stream the decrypted file
to STDOUT for use in pipes (i.e., mplayer movie
viewing, xv image viewing, etc.).