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mcrypt_get_iv_size

(PHP 4 >= 4.0.2, PHP 5, PHP 7 < 7.2.0, PECL mcrypt >= 1.0.0)

mcrypt_get_iv_sizeReturns 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

mcrypt_get_iv_size(string $cipher, string $mode): int

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

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User Contributed Notes 1 note

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Hernanibus
7 years ago
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
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