public void Encrypted_data_should_not_match_original() { var data = new EncryptData { Date = DateTime.Now.Subtract(TimeSpan.FromDays(5)), SecretText = "I am a fan of Chopin." }; const string password = "******"; var crypted = new AesEncrypter(password).Encrypt(data); var msg = Should.Throw <SerializationException>( () => ConvertByteArray.ByteArrayToObject <EncryptData>(crypted.CipherBytes)).Message; (msg.Contains("The input stream is not a valid binary format") || msg.Contains("does not contain a valid BinaryHeader")).ShouldBeTrue(); }