The size of the initialization vector (iv) will be returned in bytes NOT bits, something to keep in mind specially if the iv is passed together appended or prepended with the encrypted data for decryption
mcrypt_get_iv_size
(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
Advertencia
Esta función ha sido declarada OBSOLETA a partir de PHP 7.1.0 y será ELIMINADA a partir de PHP 7.2.0. Su uso está totalmente desaconsejado.
Descripción
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().
Parámetros
-
cipher -
Una de las constantes
MCRYPT_nombredelcifrado, o el nombre del algoritmo como string. -
mode -
Una de las constantes
MCRYPT_MODE_nombredelmodo, o una de las siguientes strings: "ecb", "cbc", "cfb", "ofb", "nofb" o "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.
Valores devueltos
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.
Ejemplos
Ejemplo #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";
?>Ver también
- 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
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User Contributed Notes 1 note
Hernanibus ¶
8 years ago
