mcrypt_create_iv

Description

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.

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); ?>