CSPRNG Functions
PHP Manual

random_int

Generates cryptographically secure pseudo-random integers

Description

int random_int ( int $min , int $max )

Generates cryptographic random integers that are suitable for use where unbiased results are critical, such as when shuffling a deck of cards for a poker game.

The sources of randomness used for this function are as follows:

  • On Windows, » CryptGenRandom will always be used.
  • On Linux, the » getrandom(2) syscall will be used if available.
  • On other platforms, /dev/urandom will be used.
  • If none of the aforementioned sources are available, then an Exception will be thrown.

Note: Although this function was added to PHP in PHP 7.0, a » userland implementation is available for PHP 5.2 to 5.6, inclusive.

Parameters

min

The lowest value to be returned, which must be PHP_INT_MIN or higher.

max

The highest value to be returned, which must be less than or equal to PHP_INT_MAX.

Return Values

Returns a cryptographically secure random integer in the range min to max, inclusive.

Errors/Exceptions

  • If an appropriate source of randomness cannot be found, an Exception will be thrown.
  • If invalid parameters are given, a TypeError will be thrown.
  • If max is less than min, an Error will be thrown.

Examples

Example #1 random_int example

<?php
var_dump(random_int(100, 999));
var_dump(random_int(-1000, 0));
?>

The above example will output something similar to:

int(248)
int(-898)

See Also

  • random_bytes