Mcrypt Funciones
PHP Manual

mcrypt_create_iv

(PHP 4, PHP 5)

mcrypt_create_ivCreate an initialization vector (IV) from a random source

Descripción

string mcrypt_create_iv ( int $size [, int $source = MCRYPT_DEV_RANDOM ] )

Create an initialization vector (IV) from a random source.

The IV is only meant to give an alternative seed to the encryption routines. This IV does not need to be secret at all, though it can be desirable. You even can send it along with your ciphertext without losing security.

Parámetros

size

Determines the size of the IV, parameter source (defaults to random value) specifies the source of the IV.

source

The source can be MCRYPT_RAND (system random number generator), MCRYPT_DEV_RANDOM (read data from /dev/random) and MCRYPT_DEV_URANDOM (read data from /dev/urandom). Prior to 5.3.0, MCRYPT_RAND was the only one supported on Windows.

Valores devueltos

Returns the initialization vector, or FALSE on error.

Historial de cambios

Versión Descripción
5.3.0 MCRYPT_DEV_RANDOM and MCRYPT_DEV_URANDOM became available on Windows platforms.
5.3.0 It is no longer required to call srand() first. This is now done automatically.

Ejemplos

Example #1 mcrypt_create_iv() example

<?php
    $size 
mcrypt_get_iv_size(MCRYPT_CAST_256MCRYPT_MODE_CFB);
    
$iv mcrypt_create_iv($sizeMCRYPT_DEV_RANDOM);
?>

Ver también


Mcrypt Funciones
PHP Manual