In PHP, how do I generate a big pseudo-random number?

Question

I\'m looking for a way to generate a big random number with PHP, something like:

mt_rand($lower, $upper);

The closer I\'ve

Answer 1

This question was asked like decade ago but for folks that come from Google propper answer is gmp_random_range("min_value", "max_value") funciton.

$range=gmp_random_range("1225468798745475454898787465154", "1225468798745475454898787465200");
echo gmp_strval($range); // displays value as string

Answer 2

What you really need to know is the relative gap; if it's small then you can generate a number from 0 to the maximum gap then add the minimum to that.

Answer 3

What you can do is create a few smaller random numbers and combine them. Not sure on how large you actually need though.

Answer 4

Tested and works

<?php 

$min = "1225468798745475454898787465154";
$max = "1225468798745475454898787465200";

$bigRandNum = bigRandomNumber($min,$max);
echo "The Big Random Number is: ".$bigRandNum."<br />";

function bigRandomNumber($min,$max) {
    // take the max number length
    $number_length = strlen($max);

    // Set the counter
    $i = 1;

    // Find the base and the min and max ranges
    // Loop through the min to find the base number
    while ($i <= $number_length) {
        $sub_string = substr($min, 0, $i);

        // format pattern
        $format_pattern = '/'.$sub_string.'/';
        if (!preg_match($format_pattern, $max)) {
            $base = $sub_string;

            // Set the min and max ranges
            $minRange = substr($min, ($i - 1), $number_length);
            $maxRange = substr($max, ($i - 1), $number_length);

            // End while loop, we found the base
            $i = $number_length;
        }
        $i++;
    }
    // find a random number with the min and max range
    $rand = rand($minRange, $maxRange);

    // add the base number to the random number
    $randWithBase = $base.$rand;

    return $randWithBase;
}

?>

Answer 5

$lower = gmp_com("1225468798745475454898787465154");
$upper = gmp_com("1225468798745475454898787465200");

$range_size = gmp_sub($upper, $lower);

$rand = gmp_random(31);
$rand = gmp_mod($rand, $range_size);

$result = gmp_add($rand, $lower);

Totally untested :-)

Answer 6

Take your floor and and your random number in the range to it.

1225468798745475454898787465154 + rand(0, 6)