mcrypt_create_iv

(PHP 3>= 3.0.8, 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.