mcrypt_get_iv_size

(PHP 4 >= 4.0.2, PHP 5)

mcrypt_get_iv_size — Returns the size of the IV belonging to a specific cipher/mode combination

Описание

int mcrypt_get_iv_size ( string $cipher , string $mode )

Gets the size of the IV belonging to a specific cipher/mode combination.

It is more useful to use the mcrypt_enc_get_iv_size() function as this uses the resource returned by mcrypt_module_open().

Список параметров

cipher: One of the MCRYPT_ciphername constants, or the name of the algorithm as string.
mode: One of the MCRYPT_MODE_modename constants, or one of the following strings: "ecb", "cbc", "cfb", "ofb", "nofb" or "stream". The IV is ignored in ECB mode as this mode does not require it. You will need to have the same IV (think: starting point) both at encryption and decryption stages, otherwise your encryption will fail.

Возвращаемые значения

Returns the size of the Initialization Vector (IV) in bytes. On error the function returns FALSE. If the IV is ignored in the specified cipher/mode combination zero is returned.

Примеры

Пример #1 mcrypt_get_iv_size() Example


<?php
    echo mcrypt_get_iv_size(MCRYPT_CAST_256, MCRYPT_MODE_CFB) . "\n";

    echo mcrypt_get_iv_size('des', 'ecb') . "\n";
?>

Смотрите также

mcrypt_get_block_size() - Gets the block size of the specified cipher
mcrypt_enc_get_iv_size() - Returns the size of the IV of the opened algorithm
mcrypt_create_iv() - Creates an initialization vector (IV) from a random source