private void TestSHA512AndAssert(Key key, int digits, DateTime time, string expected)
 {
     var otp = new TimeBasedOtpGenerator(key, digits, new SHA512HMACAlgorithm());
     var result = otp.GenerateOtp(time);
     Assert.AreEqual(expected, result);
 }
 private string GetOtpWithImplicitHMAC(Key key, int digits, DateTime time)
 {
     var otp = new TimeBasedOtpGenerator(key, digits);
     return otp.GenerateOtp(time);
 }