(3.0.8 - 3.0.18 only, PHP 4 >= 4.0.0)
mcrypt_create_iv -- Create an initialization vector (IV) from a random source
Description
string mcrypt_create_iv (int size, int source)
mcrypt_create_iv() is used to create an IV.
mcrypt_create_iv() takes two arguments, size determines the size of
the IV, source specifies 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). If you use
MCRYPT_RAND, make sure to call srand() before to initialize the random number generator.
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Example 1. mcrypt_create_iv() example
<?php
$cipher = MCRYPT_TripleDES;
$block_size = mcrypt_get_block_size ($cipher);
$iv = mcrypt_create_iv ($block_size, MCRYPT_DEV_RANDOM);
?>
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