FOF30\TransparentAuthentication\TransparentAuthentication::decryptWithTOTP PHP Метод

    private function decryptWithTOTP($encryptedData)
    {
        if (empty($this->totpKey)) {
            $this->cryptoKey = null;
            return null;
        }
        $totp = new Totp($this->timeStep);
        $period = $totp->getPeriod();
        $period--;
        for ($i = 0; $i <= 2; $i++) {
            $time = ($period + $i) * $this->timeStep;
            $otp = $totp->getCode($this->totpKey, $time);
            $this->cryptoKey = hash('sha256', $this->totpKey . $otp);
            $aes = new Aes($this->cryptoKey);
            try {
                $ret = $aes->decryptString($encryptedData);
            } catch (\Exception $e) {
                continue;
            }
            $ret = rtrim($ret, "");
            $ret = json_decode($ret, true);
            if (!is_array($ret)) {
                continue;
            }
            if (!array_key_exists('username', $ret)) {
                continue;
            }
            if (!array_key_exists('password', $ret)) {
                continue;
            }
            // Successful decryption!
            return $ret;
        }
        // Obviously if we're here we could not decrypt anything. Bail out.
        $this->cryptoKey = null;
        return null;
    }