Create Auth Tokens with PHP

auth_token.php

function create_auth_token($length = 64)
{
    if (!$length || intval($length) <= 8) {
        $length = 64;
    }
    $bytes = null;
    if (function_exists('random_bytes')) {
        $bytes = random_bytes($length);
    } elseif (function_exists('mcrypt_create_iv')) {
        $bytes = mcrypt_create_iv($length, MCRYPT_DEV_URANDOM);
    } elseif (function_exists('openssl_random_pseudo_bytes')) {
        $bytes = openssl_random_pseudo_bytes($length);
    }

    return $bytes ? bin2hex($bytes) : false;
}