(PHP 4 >= 4.0.2, PHP 5, PHP 7) Checks whether the encryption of the opened mode works on blocks

(PHP 4, PHP 5, PHP 7) Gets the block size of the specified cipher

(PHP 4 >= 4.0.2, PHP 5, PHP 7) Returns the size of the IV of the opened algorithm

(PHP 4, PHP 5) Encrypts/decrypts data in CFB mode

(PHP 4, PHP 5, PHP 7) Creates an initialization vector (IV) from a random source

(PHP 4 >= 4.0.2, PHP 5) This function terminates encryption

(PHP 4, PHP 5) Encrypts/decrypts data in OFB mode