PHP. Руководство по PHP. 2005
mcrypt_create_iv
mcrypt_create_iv
(PHP 3>= 3.0.8, PHP 4, PHP 5)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.
Parameter size determines the size of the IV, parameter source (defaults to random value) 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). MCRYPT_RAND is the only one supported on Windows because Windows (of course) doesn't have /dev/random or /dev/urandom.
Замечание: When using MCRYPT_RAND, remember to call srand() before mcrypt_create_iv() to initialize the random number generator; it is not seeded automatically like rand() is.
