PHP 7.0.6 Released

    random_int

    (PHP 7)

    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() - Generates cryptographically secure pseudo-random bytes

    User Contributed Notes

    info at raymondrodgers dot com
    3 months ago
    This function is based on Andrew Moore's UUID generation function on the uniqid function; it has been updated to use random_int() on PHP 7.0 or later yet continue to function with earlier versions using mt_rand().

    function generateUUIDv4()
    {
        if(version_compare(PHP_VERSION,'7.0.0', '<') )
        {
            return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
           
            // 32 bits for "time_low"
            mt_rand(0, 0xffff), mt_rand(0, 0xffff),
           
            // 16 bits for "time_mid"
            mt_rand(0, 0xffff),
           
            // 16 bits for "time_hi_and_version",
            // four most significant bits holds version number 4
            mt_rand(0, 0x0fff) | 0x4000,
           
            // 16 bits, 8 bits for "clk_seq_hi_res",
            // 8 bits for "clk_seq_low",
            // two most significant bits holds zero and one for variant DCE1.1
            mt_rand(0, 0x3fff) | 0x8000,
           
            // 48 bits for "node"
            mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
            );
        }
        else
        {
            return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
           
            // 32 bits for "time_low"
            random_int(0, 0xffff), random_int(0, 0xffff),
           
            // 16 bits for "time_mid"
            random_int(0, 0xffff),
           
            // 16 bits for "time_hi_and_version",
            // four most significant bits holds version number 4
            random_int(0, 0x0fff) | 0x4000,
           
            // 16 bits, 8 bits for "clk_seq_hi_res",
            // 8 bits for "clk_seq_low",
            // two most significant bits holds zero and one for variant DCE1.1
            random_int(0, 0x3fff) | 0x8000,
           
            // 48 bits for "node"
            random_int(0, 0xffff), random_int(0, 0xffff), random_int(0, 0xffff)
            );
        }
    }
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