private static Lazy <SafeAlgorithmHandle> Open3DesAlgorithm(string cipherMode, int feedback = 0)
{
return(new Lazy <SafeAlgorithmHandle>(() =>
{
SafeAlgorithmHandle hAlg = Cng.BCryptOpenAlgorithmProvider(Cng.BCRYPT_3DES_ALGORITHM, null,
Cng.OpenAlgorithmProviderFlags.NONE);
hAlg.SetCipherMode(cipherMode);
// The default feedback size is 1 (CFB8) on Windows. Do not set the CNG property
// if we would be setting it to the default. Windows 7 only supports CFB8 and
// does not permit setting the feedback size, so we don't call the property
// setter at all in that case.
if (feedback > 0 && feedback != 1)
{
try
{
hAlg.SetFeedbackSize(feedback);
}
catch (CryptographicException ex)
{
throw new CryptographicException(SR.Cryptography_FeedbackSizeNotSupported, ex);
}
}
return hAlg;
}));
}
private static SafeAlgorithmHandle GetCachedAlgorithmHandle(ref SafeAlgorithmHandle?handle, string algId, string?chainingMode = null)
{
// Do we already have a handle to this algorithm?
SafeAlgorithmHandle?existingHandle = Volatile.Read(ref handle);
if (existingHandle != null)
{
return(existingHandle);
}
// No cached handle exists; create a new handle. It's ok if multiple threads call
// this concurrently. Only one handle will "win" and the rest will be destroyed.
SafeAlgorithmHandle newHandle = Cng.BCryptOpenAlgorithmProvider(algId, null, Cng.OpenAlgorithmProviderFlags.NONE);
if (chainingMode != null)
{
newHandle.SetCipherMode(chainingMode);
}
existingHandle = Interlocked.CompareExchange(ref handle, newHandle, null);
if (existingHandle != null)
{
newHandle.Dispose();
return(existingHandle);
}
else
{
return(newHandle);
}
}
private static SafeAlgorithmHandle Open3DesAlgorithm(string cipherMode)
{
SafeAlgorithmHandle hAlg = Cng.BCryptOpenAlgorithmProvider(Cng.BCRYPT_3DES_ALGORITHM, null, Cng.OpenAlgorithmProviderFlags.NONE);
hAlg.SetCipherMode(cipherMode);
return(hAlg);
}
private static Lazy <SafeAlgorithmHandle> OpenDesAlgorithm(string cipherMode)
{
return(new Lazy <SafeAlgorithmHandle>(() =>
{
SafeAlgorithmHandle hAlg = Cng.BCryptOpenAlgorithmProvider(
Cng.BCRYPT_DES_ALGORITHM,
null,
Cng.OpenAlgorithmProviderFlags.NONE);
hAlg.SetCipherMode(cipherMode);
return hAlg;
}));
}
private static SafeAlgorithmHandle OpenRC2Algorithm(string cipherMode, int effectiveKeyLength)
{
SafeAlgorithmHandle hAlg = Cng.BCryptOpenAlgorithmProvider(Cng.BCRYPT_RC2_ALGORITHM, null, Cng.OpenAlgorithmProviderFlags.NONE);
hAlg.SetCipherMode(cipherMode);
if (effectiveKeyLength != 0)
{
Cng.SetEffectiveKeyLength(hAlg, effectiveKeyLength);
}
return(hAlg);
}
private static Lazy <SafeAlgorithmHandle> Open3DesAlgorithm(string cipherMode, int feedback = 0)
{
return(new Lazy <SafeAlgorithmHandle>(() =>
{
SafeAlgorithmHandle hAlg = Cng.BCryptOpenAlgorithmProvider(Cng.BCRYPT_3DES_ALGORITHM, null,
Cng.OpenAlgorithmProviderFlags.NONE);
hAlg.SetCipherMode(cipherMode);
if (feedback > 0)
{
// feedback is in bytes!
hAlg.SetFeedbackSize(feedback);
}
return hAlg;
}));
}
