token.php

<?php
function crypto_rand_secure($min, $max)
{
    $range = $max - $min;
    if ($range < 0) return $min; // not so random...
    $log = log($range, 2);
    $bytes = (int)($log / 8) + 1; // length in bytes
    $bits = (int)$log + 1; // length in bits
    $filter = (int)(1 << $bits) - 1; // set all lower bits to 1
    do {
        $rnd = hexdec(bin2hex(openssl_random_pseudo_bytes($bytes)));
        $rnd = $rnd & $filter; // discard irrelevant bits
    } while ($rnd >= $range);
    return $min + $rnd;
}

function getToken($length=32){
    $token = "";
    $codeAlphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    $codeAlphabet.= "abcdefghijklmnopqrstuvwxyz";
    $codeAlphabet.= "0123456789";
    for($i=0;$i<$length;$i++){
        $token .= $codeAlphabet[crypto_rand_secure(0,strlen($codeAlphabet))];
    }
    return $token;
}