(PHP 4 >= 4.0.2, PHP 5, PHP 7 < 7.2.0, PECL mcrypt >= 1.0.0)
mcrypt_get_iv_size — Returns the size of the IV belonging to a specific cipher/mode combination
Ця функція ЗАСТАРІЛА, починаючи з PHP 7.1.0, та ВИЛУЧЕНА в PHP 7.2.0. Вкрай не рекомендується на неї покладатися.
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().
cipherОдна з констант
MCRYPT_ciphername або назва алгоритму у вигляді
рядка.
modeОдна з констант
MCRYPT_MODE_modename або один з рядків: "ecb", "cbc",
"cfb", "ofb", "nofb", "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.
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.
Приклад #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";
?>