&reftitle.examples; Mcrypt can be used to encrypt and decrypt using the above mentioned ciphers. If you linked against libmcrypt-2.2.x, the four important mcrypt commands (mcrypt_cfb, mcrypt_cbc, mcrypt_ecb, and mcrypt_ofb) can operate in both modes which are named MCRYPT_ENCRYPT and MCRYPT_DECRYPT, respectively. If you linked against libmcrypt 2.4.x or 2.5.x, these functions are still available, but it is recommended that you use the advanced functions. ]]> This example will give you the encrypted data as a string in $encrypted_data. For a full example see mcrypt_module_open.