internal BCryptHMAC(CngAlgorithm algorithm,
CngProvider algorithmProvider,
string hashName,
int blockSize,
byte[] key)
{
Debug.Assert(algorithm != null, "algorithm != null");
Debug.Assert(algorithmProvider != null, "algorithmProvider != null");
Debug.Assert(!String.IsNullOrEmpty(hashName), "!String.IsNullOrEmpty(hashName)");
Debug.Assert(blockSize > 0, "blockSize > 0");
Debug.Assert(key != null, "key != null");
BlockSizeValue = blockSize;
HashName = hashName;
m_algorithm = BCryptNative.OpenAlgorithm(algorithm.Algorithm,
algorithmProvider.Provider,
BCryptNative.AlgorithmProviderOptions.HmacAlgorithm);
// Resetting the key will call Initialize for us, and get us setup with a hash handle,
// so we don't need to create the hash handle ourselves
Key = key;
HashSizeValue = BCryptNative.GetInt32Property(m_hash, BCryptNative.HashPropertyName.HashLength) * 8;
}
internal BCryptHMAC(CngAlgorithm algorithm,
CngProvider algorithmProvider,
string hashName,
int blockSize,
byte[] key)
{
Debug.Assert(algorithm != null, "algorithm != null");
Debug.Assert(algorithmProvider != null, "algorithmProvider != null");
Debug.Assert(!String.IsNullOrEmpty(hashName), "!String.IsNullOrEmpty(hashName)");
Debug.Assert(blockSize > 0, "blockSize > 0");
Debug.Assert(key != null, "key != null");
BlockSizeValue = blockSize;
// We set the HashName up to be the CNG version of the hash, since the base type will instantiate
// the algorithm, and the CNG versions have different FIPS characteristics than the standard implementations.
HashName = String.Format(CultureInfo.InvariantCulture,
"System.Security.Cryptography.{0}Cng, {1}",
hashName,
typeof(SHA256Cng).Assembly.FullName);
m_implementation = algorithmProvider;
m_algorithm = BCryptNative.OpenAlgorithm(algorithm.Algorithm,
algorithmProvider.Provider,
BCryptNative.AlgorithmProviderOptions.HmacAlgorithm);
// Resetting the key will call Initialize for us, and get us setup with a hash handle,
// so we don't need to create the hash handle ourselves
Key = key;
HashSizeValue = BCryptNative.GetInt32Property(m_hash, BCryptNative.HashPropertyName.HashLength) * 8;
}
private void UpdateLegalTagSizes()
{
using (SafeBCryptAlgorithmHandle algorithm = SetupAlgorithm())
{
UpdateLegalTagSizes(algorithm);
}
}
internal static extern ErrorCode BCryptCreateHash(SafeBCryptAlgorithmHandle hAlgorithm,
[Out] out SafeBCryptHashHandle hHash,
IntPtr pbHashObject, // byte *
int cbHashObject,
[In, MarshalAs(UnmanagedType.LPArray)] byte[] pbSecret,
int cbSecret,
int dwFlags);
internal BCryptAuthenticatedSymmetricAlgorithm(CngAlgorithm algorithm,
CngProvider implementation,
KeySizes[] legalBlockSizes,
KeySizes[] legalKeySizes)
{
Debug.Assert(algorithm != null, "algorithm != null");
Debug.Assert(implementation != null, "implementation != null");
Debug.Assert(legalBlockSizes != null, "legalBlockSizes != null");
Debug.Assert(legalKeySizes != null, "legalKeySizes != null");
m_algorithm = algorithm;
m_implementation = implementation;
m_chainingMode = CngChainingMode.Gcm;
LegalBlockSizesValue = legalBlockSizes;
LegalKeySizesValue = legalKeySizes;
// Create a temporary algorithm handle so that we can query it for some properties - such as the
// block and tag sizes.
using (SafeBCryptAlgorithmHandle algorithmHandle = SetupAlgorithm())
{
// Get block size in bits
BlockSize = BCryptNative.GetInt32Property(algorithmHandle, BCryptNative.ObjectPropertyName.BlockLength) * 8;
UpdateLegalTagSizes(algorithmHandle);
}
}
internal static extern ErrorCode BCryptImportKey(SafeBCryptAlgorithmHandle hAlgorithm,
IntPtr hImportKey,
[MarshalAs(UnmanagedType.LPWStr)] string pszBlobType,
[Out] out SafeBCryptKeyHandle phKey,
[In, Out] IntPtr pbKeyObject, // BYTE *
int cbKeyObject,
[In, MarshalAs(UnmanagedType.LPArray)] byte[] pbInput,
int cbInput,
int dwFlags);
internal BCryptAuthenticatedSymmetricCryptoTransform(SafeBCryptAlgorithmHandle algorithm,
byte[] key,
byte[] nonce,
byte[] authenticatedData,
bool chainingSupported,
int tagSize) :
this(algorithm, key, nonce, authenticatedData, new byte[tagSize / 8], chainingSupported)
{
m_encrypting = true;
}
public RNGCng(CngProvider algorithmProvider)
{
if (algorithmProvider == null)
{
throw new ArgumentNullException("algorithmProvider");
}
m_algorithm = BCryptNative.OpenAlgorithm(BCryptNative.AlgorithmName.Rng,
algorithmProvider.Provider);
}
internal static SafeBCryptHashHandle CreateHash(SafeBCryptAlgorithmHandle algorithm,
byte[] secret)
{
Debug.Assert(algorithm != null, "algorithm != null");
Debug.Assert(!algorithm.IsClosed && !algorithm.IsInvalid, "!algorithm.IsClosed && !algorithm.IsInvalid");
IntPtr hashObject = IntPtr.Zero;
SafeBCryptHashHandle hash = null;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
// Figure out how big of a buffer is needed for the hash object and allocate it
int hashObjectSize = GetInt32Property(algorithm, ObjectPropertyName.ObjectLength);
RuntimeHelpers.PrepareConstrainedRegions();
try { }
finally
{
hashObject = Marshal.AllocCoTaskMem(hashObjectSize);
}
// Create the hash object
ErrorCode error = UnsafeNativeMethods.BCryptCreateHash(algorithm,
out hash,
hashObject,
hashObjectSize,
secret,
secret != null ? secret.Length : 0,
0);
if (error != ErrorCode.Success)
{
throw new CryptographicException((int)error);
}
// Transfer ownership of the buffer to the safe handle
hash.DataBuffer = hashObject;
return(hash);
}
finally
{
// If the safe hash handle never took ownership of the data buffer, free it now.
if (hashObject != IntPtr.Zero)
{
if (hash == null || hash.DataBuffer == IntPtr.Zero)
{
Marshal.FreeCoTaskMem(hashObject);
}
}
}
}
private SafeBCryptAlgorithmHandle SetupAlgorithm()
{
// Open the algorithm handle
SafeBCryptAlgorithmHandle algorithm =
BCryptNative.OpenAlgorithm(m_algorithm.Algorithm, m_implementation.Provider);
// Set the chaining mode
BCryptNative.SetStringProperty(algorithm,
BCryptNative.ObjectPropertyName.ChainingMode,
m_chainingMode.ChainingMode);
return(algorithm);
}
private SafeBCryptAlgorithmHandle SetupAlgorithm()
{
SafeBCryptAlgorithmHandle algorithmHandle = BCryptNative.OpenAlgorithm(m_algorithm.Algorithm, m_algorithmProvider.Provider);
// If we've selected a different block size than the default, set that now
if (BlockSize / 8 != BCryptNative.GetInt32Property(algorithmHandle, BCryptNative.ObjectPropertyName.BlockLength))
{
BCryptNative.SetInt32Property(algorithmHandle, BCryptNative.ObjectPropertyName.BlockLength, BlockSize / 8);
}
BCryptNative.SetStringProperty(algorithmHandle, BCryptNative.ObjectPropertyName.ChainingMode, BCryptNative.MapChainingMode(Mode));
return(algorithmHandle);
}
internal static void GenerateRandomBytes(SafeBCryptAlgorithmHandle algorithm, byte[] buffer)
{
Debug.Assert(algorithm != null, "algorithm != null");
Debug.Assert(!algorithm.IsClosed && !algorithm.IsInvalid, "!algorithm.IsClosed && !algorithm.IsInvalid");
Debug.Assert(buffer != null, "buffer != null");
ErrorCode error = UnsafeNativeMethods.BCryptGenRandom(algorithm,
buffer,
buffer.Length,
0);
if (error != ErrorCode.Success)
{
throw new CryptographicException((int)error);
}
}
internal static SafeBCryptAlgorithmHandle OpenAlgorithm(string algorithm,
string implementation,
AlgorithmProviderOptions options)
{
Debug.Assert(!String.IsNullOrEmpty(algorithm), "!String.IsNullOrEmpty(algorithm)");
Debug.Assert(!String.IsNullOrEmpty(implementation), "!String.IsNullOrEmpty(implementation)");
SafeBCryptAlgorithmHandle algorithmHandle = null;
ErrorCode error = UnsafeNativeMethods.BCryptOpenAlgorithmProvider(out algorithmHandle,
algorithm,
implementation,
options);
if (error != ErrorCode.Success)
{
throw new CryptographicException((int)error);
}
return(algorithmHandle);
}
internal BCryptSymmetricCryptoTransform(SafeBCryptAlgorithmHandle algorithm,
byte[] key,
byte[] iv,
PaddingMode paddingMode,
bool encrypting)
{
Debug.Assert(algorithm != null, "algorithm != null");
Debug.Assert(!algorithm.IsClosed && !algorithm.IsInvalid, "!algorithm.IsClosed && !algorithm.IsInvalid");
Debug.Assert(key != null, "key != null");
m_algorithm = algorithm;
m_encrypting = encrypting;
m_paddingMode = BlockPaddingMethod.Create(paddingMode,
BCryptNative.GetInt32Property(algorithm, BCryptNative.ObjectPropertyName.BlockLength));
m_iv = ProcessIV(iv, BCryptNative.GetInt32Property(algorithm,
BCryptNative.ObjectPropertyName.BlockLength),
BCryptNative.MapChainingMode(BCryptNative.GetStringProperty(algorithm, BCryptNative.ObjectPropertyName.ChainingMode)));
m_key = BCryptNative.ImportSymmetricKey(algorithm, key);
}
private void UpdateLegalTagSizes(SafeBCryptAlgorithmHandle algorithm)
{
Debug.Assert(algorithm != null, "algorithm != null");
Debug.Assert(!algorithm.IsClosed && !algorithm.IsInvalid, "!algorithm.IsClosed && !algorithm.IsInvalid");
// Get the authentication tag length structure.
BCryptNative.BCRYPT_KEY_LENGTHS_STRUCT tagLengths =
BCryptNative.GetValueTypeProperty <SafeBCryptAlgorithmHandle, BCryptNative.BCRYPT_KEY_LENGTHS_STRUCT>(
algorithm,
BCryptNative.ObjectPropertyName.AuthTagLength);
// BCrypt returns the tag sizes in bytes, convert them to bits for the LegalTagSizes property
LegalTagSizesValue = new KeySizes[]
{
new KeySizes(tagLengths.dwMinLength * 8, tagLengths.dwMaxLength * 8, tagLengths.dwIncrement * 8)
};
// By default, generate the maximum authentication tag length possible for this algorithm
TagSize = tagLengths.dwMaxLength * 8;
}
internal BCryptAuthenticatedSymmetricCryptoTransform(SafeBCryptAlgorithmHandle algorithm,
byte[] key,
byte[] nonce,
byte[] authenticatedData,
byte[] tag,
bool chainingSupported)
{
Debug.Assert(algorithm != null, "algorithm != null");
Debug.Assert(!algorithm.IsClosed && !algorithm.IsInvalid, "!algorithm.IsClosed && !algorithm.IsInvalid");
if (key == null)
{
throw new ArgumentNullException("key");
}
if (tag == null)
{
throw new ArgumentNullException("tag");
}
bool initializationComplete = false;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
m_algorithm = algorithm;
m_key = BCryptNative.ImportSymmetricKey(algorithm, key);
// Initialize the padding info structure.
m_authInfo = new BCryptNative.BCRYPT_AUTHENTICATED_CIPHER_MODE_INFO();
BCryptNative.InitializeAuthnenticatedCipherModeInfo(ref m_authInfo);
if (nonce != null)
{
m_authInfo.cbNonce = nonce.Length;
m_authInfo.pbNonce = Marshal.AllocCoTaskMem(m_authInfo.cbNonce);
Marshal.Copy(nonce, 0, m_authInfo.pbNonce, m_authInfo.cbNonce);
}
if (authenticatedData != null)
{
m_authInfo.cbAuthData = authenticatedData.Length;
m_authInfo.pbAuthData = Marshal.AllocCoTaskMem(m_authInfo.cbAuthData);
Marshal.Copy(authenticatedData, 0, m_authInfo.pbAuthData, m_authInfo.cbAuthData);
}
if (chainingSupported)
{
m_chainingSupported = chainingSupported;
m_authInfo.cbMacContext = tag.Length;
m_authInfo.pbMacContext = Marshal.AllocCoTaskMem(m_authInfo.cbMacContext);
BCryptNative.BCRYPT_KEY_LENGTHS_STRUCT tagLengths =
BCryptNative.GetValueTypeProperty <SafeBCryptAlgorithmHandle, BCryptNative.BCRYPT_KEY_LENGTHS_STRUCT>(
algorithm,
BCryptNative.ObjectPropertyName.AuthTagLength);
m_chainData = new byte[tagLengths.dwMaxLength];
}
else
{
m_inputBuffer = new MemoryStream();
}
m_authInfo.cbTag = tag.Length;
m_authInfo.pbTag = Marshal.AllocCoTaskMem(m_authInfo.cbTag);
Marshal.Copy(tag, 0, m_authInfo.pbTag, m_authInfo.cbTag);
// Set chaining mode if supported.
if (CanChainBlocks)
{
m_authInfo.dwFlags |= BCryptNative.AuthenticatedCipherModeInfoFlags.ChainCalls;
}
initializationComplete = true;
}
finally
{
// If we failed to complete initialization we may have already allocated some native
// resources. Clean those up before leaving the constructor.
if (!initializationComplete)
{
Dispose();
}
}
}
internal static extern ErrorCode BCryptGenRandom(SafeBCryptAlgorithmHandle hAlgorithm,
[In, Out, MarshalAs(UnmanagedType.LPArray)] byte[] pbBuffer,
int cbBuffer,
int dwFlags);
internal static extern ErrorCode BCryptGetAlgorithmProperty(SafeBCryptAlgorithmHandle hObject,
[MarshalAs(UnmanagedType.LPWStr)] string pszProperty,
[In, Out, MarshalAs(UnmanagedType.LPArray)] byte[] pbOutput,
int cbOutput,
[In, Out] ref int pcbResult,
int flags);
internal static extern ErrorCode BCryptOpenAlgorithmProvider([Out] out SafeBCryptAlgorithmHandle phAlgorithm,
[MarshalAs(UnmanagedType.LPWStr)] string pszAlgId,
[MarshalAs(UnmanagedType.LPWStr)] string pszImplementation,
AlgorithmProviderOptions dwFlags);
internal static extern ErrorCode BCryptSetAlgorithmProperty(SafeBCryptAlgorithmHandle hObject,
[MarshalAs(UnmanagedType.LPWStr)] string pszProperty,
[In, MarshalAs(UnmanagedType.LPArray)] byte[] pbInput,
int cbInput,
int dwFlags);
internal static SafeBCryptKeyHandle ImportSymmetricKey(SafeBCryptAlgorithmHandle algorithm, byte[] key)
{
Debug.Assert(algorithm != null, "algorithm != null");
Debug.Assert(!algorithm.IsClosed && !algorithm.IsInvalid, "!algorithm.IsClosed && !algorithm.IsInvalid");
Debug.Assert(key != null, "buffer != null");
IntPtr keyDataBuffer = IntPtr.Zero;
SafeBCryptKeyHandle keyHandle = null;
RuntimeHelpers.PrepareConstrainedRegions();
try
{
// Build up the key blob structure in memory. BCryptImportKey requries a
// BCRYPT_KEY_DATA_BLOB header immediately followed by the raw key data.
byte[] keyBlob = new byte[Marshal.SizeOf(typeof(BCRYPT_KEY_DATA_BLOB)) + key.Length];
unsafe
{
fixed(byte *pbKeyBlob = keyBlob)
{
BCRYPT_KEY_DATA_BLOB *pkeyDataBlob = (BCRYPT_KEY_DATA_BLOB *)pbKeyBlob;
pkeyDataBlob->dwMagic = KeyBlobMagicNumber.KeyDataBlob;
pkeyDataBlob->dwVersion = 1;
pkeyDataBlob->cbKeyData = key.Length;
}
}
Buffer.BlockCopy(key, 0, keyBlob, Marshal.SizeOf(typeof(BCRYPT_KEY_DATA_BLOB)), key.Length);
// Figure out how big of a key data buffer we need and allocate space on the native heap for
// it. We cannot use a managed array here because the address needs to stay constant for
// the lifetime of the algorithm handle. Pinning for a potentially long lifetime is
// undesirable, so we use a native heap allocation instead.
int keyDataSize = GetInt32Property(algorithm, ObjectPropertyName.ObjectLength);
RuntimeHelpers.PrepareConstrainedRegions();
try { }
finally
{
keyDataBuffer = Marshal.AllocCoTaskMem(keyDataSize);
}
// Import the key
ErrorCode error = UnsafeNativeMethods.BCryptImportKey(algorithm,
IntPtr.Zero,
KeyBlobType.KeyDataBlob,
out keyHandle,
keyDataBuffer,
keyDataSize,
keyBlob,
keyBlob.Length,
0);
if (error != ErrorCode.Success)
{
throw new CryptographicException((int)error);
}
// Give the key ownership of the key data buffer
keyHandle.DataBuffer = keyDataBuffer;
return(keyHandle);
}
finally
{
// If we allocated a key data buffer, but never transfered ownership to the key handle, then
// we need to free it now otherwise it will leak.
if (keyDataBuffer != IntPtr.Zero)
{
if (keyHandle == null || keyHandle.DataBuffer == IntPtr.Zero)
{
Marshal.FreeCoTaskMem(keyDataBuffer);
}
}
}
}
