Generate a random number without uses of deterministic rand / mt_rand php function

random.php

<?php

/**
 * Generate a random number without uses of deterministic rand / mt_rand php function
 * based on https://codeascraft.com/2012/07/19/better-random-numbers-in-php-using-devurandom
 *  - Add 64 bit support
 *  - Removed mcrypt dependency (PHP7 required)
 */

function devurandom_rand($min = 0, $max = PHP_INT_MAX) {
  $diff = $max - $min;
  if ($diff < 0 || $diff > PHP_INT_MAX) {
    throw new RuntimeException("Bad range");
  }
  
  // get some random bytes from /dev/urandom
  $bytes = random_bytes(PHP_INT_SIZE);
  if ($bytes === false || strlen($bytes) != PHP_INT_SIZE) {
    throw new RuntimeException("Unable to get ".PHP_INT_SIZE." bytes");
  }
  if (PHP_INT_SIZE == 8) { // 64-bit versions
    list($higher, $lower) = array_values(unpack('N2', $bytes));
    $value = $higher << 32 | $lower;
  }
  else { // 32-bit versions
    list($value) = array_values(unpack('Nint', $bytes));
  }

  $val = $value & PHP_INT_MAX;
  $fp = (float)$val / PHP_INT_MAX; // convert to [0,1]
  return (int)(round($fp * $diff) + $min);
}