mcrypt_enc_get_iv_size

(PHP 4 >= 4.0.2, PHP 5)

mcrypt_enc_get_iv_size — Returns the size of the IV of the opened algorithm

说明

int mcrypt_enc_get_iv_size ( resource $td )

This function returns the size of the IV of the algorithm specified by the encryption descriptor in bytes. An IV is used in cbc, cfb and ofb modes, and in some algorithms in stream mode.

参数

td: The encryption descriptor.

返回值

Returns the size of the IV, or 0 if the IV is ignored by the algorithm.