(PHP4 CVS only)
mcrypt_get_iv_size -- Returns the size of the IV belonging to a specific cipher/mode combinationint mcrypt_get_iv_size (string cipher, string mode)
Mcrypt_get_iv_size() returns the size of the Initialisation Vector (IV). On error the function returns FALSE. If the IV is ignored in the specified cipher/mode combination zero is returned.
Cipher is one of the MCRYPT_ciphername constants of the name of the algorithm as string.
Mode is one of the MCRYPT_MODE_modename constants of one of "ecb", "cbc", "cfb", "ofb", "nofb" or "stream".