function keygen()

function keygen()
{
    $chars = "abcdefghijklmnopqrstuvwxyz";
    $chars .= "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    $chars .= "0123456789";
    while (1) {
        $key = '';
        srand((double) microtime() * 1000000);
        for ($i = 0; $i < 5; $i++) {
            $key .= substr($chars, (rand() % (strlen($chars))), 1);
        }
        break;
    }
    return $key;
}

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

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;
}