mcrypt_create_iv
(PHP 4, PHP 5, PHP 7 < 7.2.0, PECL mcrypt >= 1.0.0)
mcrypt_create_iv — Creates an initialization vector (IV) from a random source
Warning
This function was DEPRECATED in PHP 7.1.0, and
REMOVED in PHP 7.2.0.
Alternatives to this function include:
Description
function mcrypt_create_iv(
int $size,
int $source = MCRYPT_DEV_URANDOM):
string
Creates 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.
Parameters
size-
The size of the IV.
source-
The source of the IV. 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.
Note that the default value of this parameter was
MCRYPT_DEV_RANDOM prior to PHP 5.6.0.
Note:
Note that MCRYPT_DEV_RANDOM may block until more
entropy is available.
Return Values
Returns the initialization vector, or false on error.
Examples
Example #1 mcrypt_create_iv() Example
<?php
$size = mcrypt_get_iv_size(MCRYPT_CAST_256, MCRYPT_MODE_CFB);
$iv = mcrypt_create_iv($size, MCRYPT_DEV_RANDOM);
?>
Mcrypt Functions
Mcrypt Functions