public void Encrypt_KnownKey()
{
// Arrange
Secret kdk = new Secret(Encoding.UTF8.GetBytes("master key"));
ManagedAuthenticatedEncryptor encryptor = new ManagedAuthenticatedEncryptor(kdk,
symmetricAlgorithmFactory: Aes.Create,
symmetricAlgorithmKeySizeInBytes: 256 / 8,
validationAlgorithmFactory: () => new HMACSHA256(),
genRandom: new SequentialGenRandom());
ArraySegment <byte> plaintext = new ArraySegment <byte>(new byte[] { 0, 1, 2, 3, 4, 5, 6, 7 }, 2, 3);
ArraySegment <byte> aad = new ArraySegment <byte>(new byte[] { 7, 6, 5, 4, 3, 2, 1, 0 }, 1, 4);
// Act
byte[] retVal = encryptor.Encrypt(
plaintext: plaintext,
additionalAuthenticatedData: aad);
// Assert
// retVal := 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F (keyModifier)
// | 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F (IV)
// | B7 EA 3E 32 58 93 A3 06 03 89 C6 66 03 63 08 4B (encryptedData)
// | 9D 8A 85 C7 0F BD 98 D8 7F 72 E7 72 3E B5 A6 26 (HMAC)
// | 6C 38 77 F7 66 19 A2 C9 2C BB AD DA E7 62 00 00
string retValAsString = Convert.ToBase64String(retVal);
Assert.Equal("AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh+36j4yWJOjBgOJxmYDYwhLnYqFxw+9mNh/cudyPrWmJmw4d/dmGaLJLLut2udiAAA=", retValAsString);
}
public void Encrypt_Decrypt_Tampering_Fails()
{
// Arrange
Secret kdk = new Secret(new byte[512 / 8]);
ManagedAuthenticatedEncryptor encryptor = new ManagedAuthenticatedEncryptor(kdk,
symmetricAlgorithmFactory: Aes.Create,
symmetricAlgorithmKeySizeInBytes: 256 / 8,
validationAlgorithmFactory: () => new HMACSHA256());
ArraySegment <byte> plaintext = new ArraySegment <byte>(Encoding.UTF8.GetBytes("plaintext"));
ArraySegment <byte> aad = new ArraySegment <byte>(Encoding.UTF8.GetBytes("aad"));
byte[] validCiphertext = encryptor.Encrypt(plaintext, aad);
// Act & assert - 1
// Ciphertext is too short to be a valid payload
byte[] invalidCiphertext_tooShort = new byte[10];
Assert.Throws <CryptographicException>(() =>
{
encryptor.Decrypt(new ArraySegment <byte>(invalidCiphertext_tooShort), aad);
});
// Act & assert - 2
// Ciphertext has been manipulated
byte[] invalidCiphertext_manipulated = (byte[])validCiphertext.Clone();
invalidCiphertext_manipulated[0] ^= 0x01;
Assert.Throws <CryptographicException>(() =>
{
encryptor.Decrypt(new ArraySegment <byte>(invalidCiphertext_manipulated), aad);
});
// Act & assert - 3
// Ciphertext is too long
byte[] invalidCiphertext_tooLong = validCiphertext.Concat(new byte[] { 0 }).ToArray();
Assert.Throws <CryptographicException>(() =>
{
encryptor.Decrypt(new ArraySegment <byte>(invalidCiphertext_tooLong), aad);
});
// Act & assert - 4
// AAD is incorrect
Assert.Throws <CryptographicException>(() =>
{
encryptor.Decrypt(new ArraySegment <byte>(validCiphertext), new ArraySegment <byte>(Encoding.UTF8.GetBytes("different aad")));
});
}
public void Encrypt_Decrypt_RoundTrips()
{
// Arrange
Secret kdk = new Secret(new byte[512 / 8]);
ManagedAuthenticatedEncryptor encryptor = new ManagedAuthenticatedEncryptor(kdk,
symmetricAlgorithmFactory: Aes.Create,
symmetricAlgorithmKeySizeInBytes: 256 / 8,
validationAlgorithmFactory: () => new HMACSHA256());
ArraySegment <byte> plaintext = new ArraySegment <byte>(Encoding.UTF8.GetBytes("plaintext"));
ArraySegment <byte> aad = new ArraySegment <byte>(Encoding.UTF8.GetBytes("aad"));
// Act
byte[] ciphertext = encryptor.Encrypt(plaintext, aad);
byte[] decipheredtext = encryptor.Decrypt(new ArraySegment <byte>(ciphertext), aad);
// Assert
Assert.Equal(plaintext, decipheredtext);
}
public void CreateAuthenticatedEncryptor_RoundTripsData_ManagedImplementation(EncryptionAlgorithm encryptionAlgorithm, ValidationAlgorithm validationAlgorithm)
{
// Parse test input
int keyLengthInBits = Int32.Parse(Regex.Match(encryptionAlgorithm.ToString(), @"^AES_(?<keyLength>\d{3})_CBC$").Groups["keyLength"].Value, CultureInfo.InvariantCulture);
// Arrange
var masterKey = Secret.Random(512 / 8);
var control = new ManagedAuthenticatedEncryptor(
keyDerivationKey: masterKey,
symmetricAlgorithmFactory: () => new AesCryptoServiceProvider(),
symmetricAlgorithmKeySizeInBytes: keyLengthInBits / 8,
validationAlgorithmFactory: () => KeyedHashAlgorithm.Create(validationAlgorithm.ToString()));
var test = CreateDescriptor(encryptionAlgorithm, validationAlgorithm, masterKey).CreateEncryptorInstance();
// Act & assert - data round trips properly from control to test
byte[] plaintext = new byte[] { 1, 2, 3, 4, 5 };
byte[] aad = new byte[] { 2, 4, 6, 8, 0 };
byte[] ciphertext = control.Encrypt(new ArraySegment <byte>(plaintext), new ArraySegment <byte>(aad));
byte[] roundTripPlaintext = test.Decrypt(new ArraySegment <byte>(ciphertext), new ArraySegment <byte>(aad));
Assert.Equal(plaintext, roundTripPlaintext);
}
