protected void TryEncryptOneShot_DestinationJustRightTest(byte[] plaintext, byte[] ciphertext, PaddingMode padding, CipherMode mode, int feedbackSize = 0)
{
using (SymmetricAlgorithm alg = CreateAlgorithm())
{
int paddingSizeBytes = mode == CipherMode.CFB ? feedbackSize / 8 : alg.BlockSize / 8;
alg.Key = Key;
int expectedCiphertextSize = mode switch
{
CipherMode.ECB => alg.GetCiphertextLengthEcb(plaintext.Length, padding),
CipherMode.CBC => alg.GetCiphertextLengthCbc(plaintext.Length, padding),
CipherMode.CFB => alg.GetCiphertextLengthCfb(plaintext.Length, padding, feedbackSize),
_ => throw new NotImplementedException(),
};
Span <byte> destinationBuffer = new byte[expectedCiphertextSize];
int bytesWritten;
bool result = mode switch
{
CipherMode.ECB => alg.TryEncryptEcb(plaintext, destinationBuffer, padding, out bytesWritten),
CipherMode.CBC => alg.TryEncryptCbc(plaintext, IV, destinationBuffer, out bytesWritten, padding),
CipherMode.CFB => alg.TryEncryptCfb(plaintext, IV, destinationBuffer, out bytesWritten, padding, feedbackSize),
_ => throw new NotImplementedException(),
};
Assert.True(result, "TryEncrypt");
Assert.Equal(expectedCiphertextSize, bytesWritten);
AssertCiphertexts(ciphertext, destinationBuffer, padding, paddingSizeBytes);
}
}
protected void TryEncryptOneShot_DestinationLargerTest(byte[] plaintext, byte[] ciphertext, PaddingMode padding, CipherMode mode, int feedbackSize = 0)
{
using (SymmetricAlgorithm alg = CreateAlgorithm())
{
int paddingSizeBytes = mode == CipherMode.CFB ? feedbackSize / 8 : alg.BlockSize / 8;
alg.Key = Key;
Span <byte> largeBuffer = new byte[ciphertext.Length + 10];
Span <byte> destinationBuffer = largeBuffer.Slice(0, ciphertext.Length);
largeBuffer.Fill(0xCC);
int bytesWritten;
bool result = mode switch
{
CipherMode.ECB => alg.TryEncryptEcb(plaintext, destinationBuffer, padding, out bytesWritten),
CipherMode.CBC => alg.TryEncryptCbc(plaintext, IV, destinationBuffer, out bytesWritten, padding),
CipherMode.CFB => alg.TryEncryptCfb(plaintext, IV, destinationBuffer, out bytesWritten, padding, feedbackSize),
_ => throw new NotImplementedException(),
};
Assert.True(result, "TryEncrypt");
Assert.Equal(destinationBuffer.Length, bytesWritten);
AssertCiphertexts(ciphertext, destinationBuffer, padding, paddingSizeBytes);
AssertExtensions.FilledWith <byte>(0xCC, largeBuffer.Slice(ciphertext.Length));
}
}
protected void TryEncryptOneShot_DestinationTooSmallTest(byte[] plaintext, byte[] ciphertext, PaddingMode padding, CipherMode mode, int feedbackSize = 0)
{
if (ciphertext.Length == 0)
{
// Can't have a too small buffer for zero.
return;
}
using (SymmetricAlgorithm alg = CreateAlgorithm())
{
alg.Key = Key;
Span <byte> destinationBuffer = new byte[ciphertext.Length - 1];
int bytesWritten;
bool result = mode switch
{
CipherMode.ECB => alg.TryEncryptEcb(plaintext, destinationBuffer, padding, out bytesWritten),
CipherMode.CBC => alg.TryEncryptCbc(plaintext, IV, destinationBuffer, out bytesWritten, padding),
CipherMode.CFB => alg.TryEncryptCfb(plaintext, IV, destinationBuffer, out bytesWritten, padding, feedbackSize),
_ => throw new NotImplementedException(),
};
Assert.False(result, "TryEncrypt");
Assert.Equal(0, bytesWritten);
}
}
