private void InternalDecrypt(
ReadOnlySpan <byte> ciphertext,
Span <byte> message,
XChaChaKey key,
XChaChaNonce nonce,
ReadOnlySpan <byte> additionalData)
{
ValidateDecryptParameters(ciphertext, message, nonce);
// nsec is always null for the XChaCha AEAD construction, here we pass IntPtr.Zero.
var result = crypto_aead_xchacha20poly1305_ietf_decrypt(
ref MemoryMarshal.GetReference(message),
out var messageLength,
IntPtr.Zero,
in MemoryMarshal.GetReference(ciphertext),
(UInt64)ciphertext.Length,
in MemoryMarshal.GetReference(additionalData),
(UInt64)additionalData.Length,
in nonce.Handle,
key.Handle);
if (result != 0)
{
throw new CryptographicException("decryption failed");
}
}
private static void ValidateNonce(XChaChaNonce nonce)
{
if (nonce.IsEmpty)
{
throw new ArgumentException($"{nameof(nonce)} is empty");
}
}
/// <summary>
/// Encrypts the <paramref name="message"/> and returns the computed ciphertext.
/// </summary>
/// <param name="message">The message to encrypt.</param>
/// <param name="key">The encryption key.</param>
/// <param name="nonce">The nonce to use when encrypting the <paramref name="message"/>.</param>
/// <returns>The computed ciphertext.</returns>
public byte[] Encrypt(ReadOnlySpan <byte> message, XChaChaKey key, XChaChaNonce nonce)
{
this.ValidateMaxMessageLength(message);
var ciphertext = new byte[GetCipherTextLength(message.Length)];
this.Encrypt(message, ciphertext, key, nonce);
return(ciphertext);
}
/// <summary>
/// Decrypts the <paramref name="ciphertext"/>, verifies the authenticaion tag, and if successful,
/// returns the decrypted message.
/// </summary>
/// <param name="ciphertext">The ciphertext to decrypt.</param>
/// <param name="key">The encryption key.</param>
/// <param name="nonce">The nonce to use when decrypting the <paramref name="ciphertext"/>.</param>
/// <returns>The decrypted message.</returns>
public byte[] Decrypt(ReadOnlySpan <byte> ciphertext, XChaChaKey key, XChaChaNonce nonce)
{
var messageLength = GetPlaintextLength(ciphertext.Length);
var message = new byte[messageLength];
this.Decrypt(ciphertext, message, key, nonce);
return(message);
}
private protected override void InternalDecrypt(
ReadOnlySpan <byte> ciphertext,
Span <byte> message,
XChaChaKey key,
XChaChaNonce nonce)
{
this.InternalDecrypt(ciphertext, message, key, nonce, ReadOnlySpan <byte> .Empty);
}
/// <summary>
/// Decrypts the <paramref name="ciphertext"/>, verifies the authenticaion tag, and if successful,
/// writes the output to <paramref name="message"/>.
/// </summary>
/// <param name="ciphertext">The ciphertext to decrypt.</param>
/// <param name="message">The buffer in which to write the decrypted message.</param>
/// <param name="key">The encryption key.</param>
/// <param name="nonce">The nonce to use when decrypting the <paramref name="ciphertext"/>.</param>
/// <param name="additionalData">The associated data to use for computing the authentication tag.</param>
public void Decrypt(
ReadOnlySpan <byte> ciphertext,
Span <byte> message,
XChaChaKey key,
XChaChaNonce nonce,
ReadOnlySpan <byte> additionalData)
{
this.InternalDecrypt(ciphertext, message, key, nonce, additionalData);
}
/// <summary>
/// Encrypts the <paramref name="message"/> and writes computed ciphertext to <paramref name="ciphertext"/>.
/// </summary>
/// <param name="message">The message to encrypt.</param>
/// <param name="ciphertext">The buffer in which to write the ciphertext.</param>
/// <param name="key">The encryption key.</param>
/// <param name="nonce">The nonce to use when encrypting the <paramref name="message"/>.</param>
/// <param name="additionalData">The associated data to use for computing the authentication tag.</param>
public void Encrypt(
ReadOnlySpan <byte> message,
Span <byte> ciphertext,
XChaChaKey key,
XChaChaNonce nonce,
ReadOnlySpan <byte> additionalData)
{
InternalEncrypt(message, ciphertext, key, nonce, additionalData);
}
public void Test_Encrypt_ReturnsNonZeroCiphertext(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var nonce = XChaChaNonce.Generate();
var message = TestConstants.MessageBytes;
var ciphertext = cipher.Encrypt(message, key, nonce);
Assert.False(ciphertext.All(b => b == 0));
}
}
public void Test_Encrypt_WithAdditionalData_ReturnsNonZeroOutput()
{
using (var key = XChaChaKey.Generate())
{
var aeadCipher = new XChaChaAeadCipher();
var nonce = XChaChaNonce.Generate();
var additionalData = Encoding.UTF8.GetBytes(DateTime.Now.ToString());
var message = RandomBytesGenerator.NextBytes(1024 * 1024);
var ciphertext = aeadCipher.Encrypt(message, key, nonce, additionalData);
Assert.False(ciphertext.All(b => b == 0));
}
}
private protected override void InternalEncrypt(
ReadOnlySpan <byte> message,
Span <byte> ciphertext,
XChaChaKey key,
XChaChaNonce nonce)
{
ValidateEncryptParameters(message, ciphertext, nonce);
crypto_secretbox_xchacha20poly1305_easy(
ref MemoryMarshal.GetReference(ciphertext),
in MemoryMarshal.GetReference(message),
(UInt64)message.Length,
in nonce.Handle,
key.Handle);
}
public void Test_Decrypt_CanDecryptCiphertext(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var nonce = XChaChaNonce.Generate();
var message = TestConstants.MessageBytes;
var ciphertext = cipher.Encrypt(message, key, nonce);
var result = cipher.Decrypt(ciphertext, key, nonce);
Assert.Equal(message, result);
}
}
public void Test_Encrypt_ProducesNonZeroOutput(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var nonce = XChaChaNonce.Generate();
var message = TestConstants.MessageBytes;
var ciphertext = new byte[cipher.GetCipherTextLength(message.Length)];
cipher.Encrypt(message, ciphertext, key, nonce);
Assert.False(ciphertext.All(b => b == 0));
}
}
public void Test_Decrypt_ReturnsMessage(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var nonce = XChaChaNonce.Generate();
const int messageLength = 1024 * 1024;
var message = RandomBytesGenerator.NextBytes(messageLength);
var ciphertext = cipher.Encrypt(message, key, nonce);
var result = cipher.Decrypt(ciphertext, key, nonce);
Assert.Equal(message, result);
}
}
public void Test_Decrypt_WithAdditionalData_Success()
{
using (var key = XChaChaKey.Generate())
{
var aeadCipher = new XChaChaAeadCipher();
var nonce = XChaChaNonce.Generate();
var additionalData = Encoding.UTF8.GetBytes(DateTime.Now.ToString());
const int messageLength = 1024 * 1024;
var message = RandomBytesGenerator.NextBytes(messageLength);
var ciphertext = aeadCipher.Encrypt(message, key, nonce, additionalData);
var result = aeadCipher.Decrypt(ciphertext, key, nonce, additionalData);
Assert.Equal(message, result);
}
}
public void Test_Encrypt_NonceEmpty_ThrowsArgumentException(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var message = TestConstants.MessageBytes;
var nonce = new XChaChaNonce();
Action action = () =>
{
cipher.Encrypt(message, key, nonce);
};
var exception = Assert.Throws <ArgumentException>(action);
Assert.Equal("nonce is empty", exception.Message);
}
}
/// <summary>
/// Tries to decrypt the <paramref name="ciphertext"/>, verifies the authenticaion tag, and if successful,
/// writes the output to <paramref name="message"/>.
/// </summary>
/// <param name="ciphertext">The ciphertext to decrypt.</param>
/// <param name="message">The buffer in which to write the decrypted message.</param>
/// <param name="key">The encryption key.</param>
/// <param name="nonce">The nonce to use when decrypting the <paramref name="ciphertext"/>.</param>
/// <param name="additionalData">The associated data to use for computing the authentication tag.</param>
/// <returns>Whether the decryption succeeded.</returns>
public bool TryDecrypt(
ReadOnlySpan <byte> ciphertext,
Span <byte> message,
XChaChaKey key,
XChaChaNonce nonce,
ReadOnlySpan <byte> additionalData)
{
try
{
this.InternalDecrypt(ciphertext, message, key, nonce, additionalData);
return(true);
}
catch
{
return(false);
}
}
public void Test_Encrypt_CiphertextBufferTooSmall_ThrowsArgumentException(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var message = TestConstants.MessageBytes;
var ciphertext = Array.Empty <byte>();
var nonce = XChaChaNonce.Generate();
Action action = () =>
{
cipher.Encrypt(message, ciphertext, key, nonce);
};
var exception = Assert.Throws <ArgumentException>(action);
Assert.Equal("ciphertext buffer is not large enough", exception.Message);
}
}
public void Test_TryDecrypt_Fails_ReturnsFalse(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var nonce = XChaChaNonce.Generate();
const int messageLength = 1024 * 1024;
var message = RandomBytesGenerator.NextBytes(messageLength);
var ciphertext = new byte[cipher.GetCipherTextLength(message.Length)];
cipher.Encrypt(message, ciphertext, key, nonce);
var wrongNonce = XChaChaNonce.Generate();
var result = cipher.TryDecrypt(ciphertext, ciphertext, key, wrongNonce);
Assert.False(result);
}
}
public void Test_Decrypt_MessageBufferTooSmall_ThrowsArgumentException(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var message = Array.Empty <byte>();
var ciphertext = new byte[cipher.GetCipherTextLength(1)];
var nonce = XChaChaNonce.Generate();
Action action = () =>
{
cipher.Decrypt(ciphertext, message, key, nonce);
};
var exception = Assert.Throws <ArgumentException>(action);
Assert.Equal("message buffer is not large enough", exception.Message);
}
}
private protected override void InternalDecrypt(
ReadOnlySpan <byte> ciphertext,
Span <byte> message,
XChaChaKey key,
XChaChaNonce nonce)
{
ValidateDecryptParameters(ciphertext, message, nonce);
var returnCode = crypto_secretbox_xchacha20poly1305_open_easy(
ref MemoryMarshal.GetReference(message),
in MemoryMarshal.GetReference(ciphertext),
(UInt64)ciphertext.Length,
in nonce.Handle,
key.Handle);
if (returnCode != 0)
{
throw new CryptographicException("decryption failed");
}
}
public void Test_EncryptWithReturn_MaxMessageLengthExceeded_ThrowsException(Type cipherType)
{
unsafe
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
Action action = () =>
{
var message = new ReadOnlySpan <byte>(IntPtr.Zero.ToPointer(), int.MaxValue);
var nonce = XChaChaNonce.Generate();
cipher.Encrypt(message, key, nonce);
};
var exception = Assert.Throws <ArgumentException>(action);
Assert.Equal("message is too long", exception.Message);
}
}
}
public void Test_Decrypt_WithInvalidAdditionalData_Fails()
{
using (var key = XChaChaKey.Generate())
{
var aeadCipher = new XChaChaAeadCipher();
var nonce = XChaChaNonce.Generate().ToArray();
var additionalData = Encoding.UTF8.GetBytes(DateTime.Now.ToString());
const int messageLength = 1024 * 1024;
var message = RandomBytesGenerator.NextBytes(messageLength);
var ciphertext = aeadCipher.Encrypt(message, key, new XChaChaNonce(nonce), additionalData);
var invalidAdditionalData = Encoding.UTF8.GetBytes("banana");
Action action = () => { aeadCipher.Decrypt(ciphertext, key, new XChaChaNonce(nonce), invalidAdditionalData); };
var exception = Assert.Throws <CryptographicException>(action);
Assert.Equal("decryption failed", exception.Message);
}
}
public void Test_TryDecrypt_CanDecryptCiphertext(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var nonce = XChaChaNonce.Generate();
const int messageLength = 1024 * 1024;
var message = RandomBytesGenerator.NextBytes(messageLength);
var ciphertext = new byte[cipher.GetCipherTextLength(message.Length)];
cipher.Encrypt(message, ciphertext, key, nonce);
var decryptedMessage = new byte[messageLength];
var result = cipher.TryDecrypt(ciphertext, decryptedMessage, key, nonce);
Assert.True(result);
Assert.Equal(message, decryptedMessage);
}
}
public void Test_Decrypt_WrongNonce_ThrowsException(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var nonce = XChaChaNonce.Generate();
var message = TestConstants.MessageBytes;
var ciphertext = cipher.Encrypt(message, key, nonce);
Action action = () =>
{
var wrongNonce = XChaChaNonce.Generate();
var result = cipher.Decrypt(ciphertext, key, wrongNonce);
};
var exception = Assert.Throws <CryptographicException>(action);
Assert.Equal("decryption failed", exception.Message);
}
}
private void InternalEncrypt(
ReadOnlySpan <byte> message,
Span <byte> ciphertext,
XChaChaKey key,
XChaChaNonce nonce,
ReadOnlySpan <byte> additionalData)
{
ValidateEncryptParameters(message, ciphertext, nonce);
// nsec is always null for the XChaCha AEAD construction, here we pass IntPtr.Zero.
crypto_aead_xchacha20poly1305_ietf_encrypt(
ref MemoryMarshal.GetReference(ciphertext),
out var ciphertextLongLength,
in MemoryMarshal.GetReference(message),
(UInt64)message.Length,
in MemoryMarshal.GetReference(additionalData),
(UInt64)additionalData.Length,
IntPtr.Zero,
in nonce.Handle,
key.Handle);
}
public void Test_EncryptWithReturn_MaxMessageLengthExceeded_ThrowsException()
{
unsafe
{
using (var key = XChaChaKey.Generate())
{
var aeadCipher = new XChaChaAeadCipher();
Action action = () =>
{
var message = new ReadOnlySpan <byte>(IntPtr.Zero.ToPointer(), int.MaxValue);
var additionalData = Encoding.UTF8.GetBytes(DateTime.Now.ToString());
var nonce = XChaChaNonce.Generate();
aeadCipher.Encrypt(message, key, nonce, additionalData);
};
var exception = Assert.Throws <ArgumentException>(action);
Assert.Equal("message is too long", exception.Message);
}
}
}
public void Test_Decrypt_Fails_ThrowsCryptographicException(Type cipherType)
{
using (var key = XChaChaKey.Generate())
{
var cipher = (XChaChaSecretKeyCipher)Activator.CreateInstance(cipherType);
var nonce = XChaChaNonce.Generate();
const int messageLength = 1024 * 1024;
var message = RandomBytesGenerator.NextBytes(messageLength);
var ciphertext = new byte[cipher.GetCipherTextLength(message.Length)];
cipher.Encrypt(message, ciphertext, key, nonce);
Action action = () =>
{
var wrongNonce = XChaChaNonce.Generate();
cipher.Decrypt(ciphertext, ciphertext, key, wrongNonce);
};
var exception = Assert.Throws <CryptographicException>(action);
Assert.Equal("decryption failed", exception.Message);
}
}
/// <summary>
/// Encrypts the <paramref name="message"/> and writes computed ciphertext to <paramref name="ciphertext"/>.
/// </summary>
/// <param name="message">The message to encrypt.</param>
/// <param name="ciphertext">The buffer in which to write the ciphertext.</param>
/// <param name="key">The encryption key.</param>
/// <param name="nonce">The nonce to use when encrypting the <paramref name="message"/>.</param>
public void Encrypt(ReadOnlySpan <byte> message, Span <byte> ciphertext, XChaChaKey key, XChaChaNonce nonce)
{
this.InternalEncrypt(message, ciphertext, key, nonce);
}
private protected void ValidateEncryptParameters(ReadOnlySpan <byte> message, Span <byte> ciphertext, XChaChaNonce nonce)
{
ValidateMaxMessageLength(message);
ValidateCiphertextLength(message, ciphertext);
ValidateNonce(nonce);
}
private protected void ValidateDecryptParameters(ReadOnlySpan <byte> ciphertext, Span <byte> message, XChaChaNonce nonce)
{
ValidateMessageLength(ciphertext, message);
ValidateNonce(nonce);
}