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.