mcrypt_enc_get_supported_key_sizes Returns an array with the supported keysizes of the opened algorithm Description arraymcrypt_enc_get_supported_key_sizes resourcetd Returns an array with the key sizes supported by the algorithm specified by the encryption descriptor. If it returns an empty array then all key sizes between 1 and mcrypt_enc_get_key_size are supported by the algorithm. <function>mcrypt_enc_get_supported_key_sizes</function> example ]]> This will print: int(16) [1]=> int(24) [2]=> int(32) } ]]>