Google2FA::oath_hotp PHP Метод

    public function oath_hotp($key, $counter)
    {
        if (strlen($key) < 8) {
            throw new Exception('Secret key is too short. Must be at least 16 base 32 characters');
        }
        $bin_counter = pack('N*', 0) . pack('N*', $counter);
        // Counter must be 64-bit int
        $hash = hash_hmac('sha1', $bin_counter, $key, true);
        return str_pad(self::oath_truncate($hash), self::OTPLENGTH, '0', STR_PAD_LEFT);
    }

        $binarySeed = self::base32_decode($b32seed);
        for ($ts = $timeStamp - $window; $ts <= $timeStamp + $window; $ts++) {
            if (self::oath_hotp($binarySeed, $ts) == $key) {
                return true;
            }
        }
        return false;
    }
    public static function oath_truncate($hash)
    {
        $offset = ord($hash[19]) & 0xf;
        return ((ord($hash[$offset + 0]) & 0x7f) << 24 | (ord($hash[$offset + 1]) & 0xff) << 16 | (ord($hash[$offset + 2]) & 0xff) << 8 | ord($hash[$offset + 3]) & 0xff) % pow(10, self::otpLength);
    }
}
$InitalizationKey = "SMARTCUBEDEEPERA";
// Set the inital key
$TimeStamp = Google2FA::get_timestamp();
$secretkey = Google2FA::base32_decode($InitalizationKey);
// Decode it into binary
$otp = Google2FA::oath_hotp($secretkey, $TimeStamp);
// Get current token
//echo("Init key: $InitalizationKey\n");
//echo("Timestamp: $TimeStamp\n");
//echo("One time password: $otp\n");
// Use this to verify a key as it allows for some time drift.
$result = Google2FA::verify_key($InitalizationKey, $_GET["password"]);
if ($result) {
    echo "true";
} else {
    echo "false";
}