These functions work using » mcrypt.
To use it, download libmcrypt-x.x.tar.gz from » http://mcrypt.sourceforge.net/ and follow the included
installation instructions. Windows users will find all the
needed compiled mcrypt binaries at
As of PHP 5.0.0 you will need libmcrypt Version 2.5.6 or greater.
If you linked against libmcrypt 2.4.x or higher, the following additional
block algorithms are supported: CAST, LOKI97, RIJNDAEL, SAFERPLUS,
SERPENT and the following stream ciphers: ENIGMA (crypt), PANAMA, RC4 and
WAKE. With libmcrypt 2.4.x or higher another cipher mode is also