mcrypt_cfb Encrypt/decrypt data in CFB mode stringmcrypt_cfb intcipher stringkey stringdata intmode stringiv stringmcrypt_cfb stringcipher stringkey stringdata intmode stringiv The first prototype is when linked against libmcrypt 2.2.x, the second when linked against libmcrypt 2.4.x or higher. The mode should be either MCRYPT_ENCRYPT or MCRYPT_DECRYPT. This function should not be used anymore, see mcrypt_generic and mdecrypt_generic for replacements.