No cache version.

Caching disabled. Default setting for this page:enabled (code LNG204)
If the display is too slow, you can disable the user mode to view the cached version.

mcrypt_create_iv

Contents

(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:

random_bytes()

Description

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.

PHP: mcrypt_create_iv - Manual Home of Manuel PHP Contents Haut

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.

PHP: mcrypt_create_iv - Manual Home of Manuel PHP Contents Haut

Return Values

Returns the initialization vector, or FALSE on error.

PHP: mcrypt_create_iv - Manual Home of Manuel PHP Contents Haut

Changelog

Version	Description
5.6.0	`MCRYPT_DEV_URANDOM` is now the default value of `source`.
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.

PHP: mcrypt_create_iv - Manual Home of Manuel PHP Contents Haut

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);
?>

PHP: mcrypt_create_iv - Manual Home of Manuel PHP Contents Haut

You have asked to visit this site in English. For now, only the interface is translated, but not all the content yet.

If you want to help me in translations, your contribution is welcome. All you need to do is register on the site, and send me a message asking me to add you to the group of translators, which will give you the opportunity to translate the pages you want. A link at the bottom of each translated page indicates that you are the translator, and has a link to your profile.

Thank you in advance.

Document created the 30/01/2003, last modified the 26/10/2018
Source of the printed document:https://www.gaudry.be/en/php-rf-function.mcrypt-create-iv.html

The infobrol is a personal site whose content is my sole responsibility. The text is available under CreativeCommons license (BY-NC-SA). More info on the terms of use and the author.

References

Manuel PHP : http://php.net

These references and links indicate documents consulted during the writing of this page, or which may provide additional information, but the authors of these sources can not be held responsible for the content of this page.
The author This site is solely responsible for the way in which the various concepts, and the freedoms that are taken with the reference works, are presented here. Remember that you must cross multiple source information to reduce the risk of errors.

Contents Haut