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

Big Integers are from 1-20 range. So generate a number using mt_rand($lower, $upper) and multiply with another mt_rand($lower, $upper)

$N1=mt_rand($lower, $upper);
$N2=mt_rand($lower, $upper);
$N3=$N1*N2;

Note:multiplication of n-digits with n-digits gives you n*2 digits.

Answer 2

Try the following:

function BigRandomNumber($min, $max) {
  $difference   = bcadd(bcsub($max,$min),1);
  $rand_percent = bcdiv(mt_rand(), mt_getrandmax(), 8); // 0 - 1.0
  return bcadd($min, bcmul($difference, $rand_percent, 8), 0);
}

The math is as following: multiply the difference between the minimum and maximum by a random percentage, and add to the minimum (with rounding to an int).