/// <summary>
/// Gets the hash parameter. This method wraps the underlying
/// api to obtain the length of the result and appropriately
/// size a result byte buffer.
/// </summary>
///
/// <param name="hashHandle">
/// The hash handle.
/// </param>
///
/// <param name="hashParameter">
/// The hash parameter.
/// </param>
///
/// <returns>
/// <c>true</c> if successful, otherwise <c>false</c>.
/// </returns>
internal static byte[] GetHashParameterWrapper(
SafeCryptoHashHandle hashHandle,
HashParameter hashParameter)
{
int hashLength = 0;
if (!UnsafeNativeMethods.CryptGetHashParam(
hashHandle, hashParameter, null, ref hashLength, 0))
{
throw new CryptographicException(Marshal.GetLastWin32Error());
}
byte[] hash = new byte[hashLength];
if (!UnsafeNativeMethods.CryptGetHashParam(
hashHandle, hashParameter, hash, ref hashLength, 0))
{
throw new CryptographicException(Marshal.GetLastWin32Error());
}
return hash;
}
/// <summary>
/// Initializes this instance.
/// </summary>
internal void Initialize()
{
Reset();
if (!UnsafeNativeMethods.CryptAcquireContext(
out _cryptoContextHandle,
null,
_provider,
_providerType,
CryptoAcquireContextFlags.None
| CryptoAcquireContextFlags.VerifyContext))
{
throw new CryptographicException(Marshal.GetLastWin32Error());
}
_cryptoHashHandle = NewHashHandle();
}
internal static extern bool CryptSetHashParam(
SafeCryptoHashHandle hash,
HashParameter paramter,
[In, Out] ref HMAC_INFO hmacInfo,
uint flags
);
/// <summary>
/// Wraps the CryptHashData method to marshal the correct
/// byte pointer.
/// </summary>
///
/// <param name="hash">
/// The hash handle.
/// </param>
///
/// <param name="data">
/// The data to hash.
/// </param>
///
/// <param name="offset">
/// The offset into the data.
/// </param>
///
/// <param name="count">
/// The count of bytes to hash.
/// </param>
internal static void CryptHashDataWrapper(
SafeCryptoHashHandle hash,
byte[] data,
int offset,
int count)
{
// We could marshal the data as UnmanagedType.LPArray but we would
// have to copy the array so that the first byte is at pos 0. This
// way we can take correct the region of the array in situ.
unsafe
{
fixed (byte* b = &data[offset])
{
IntPtr intPtr = new IntPtr((void*)b);
if (!UnsafeNativeMethods.CryptHashData(
hash, intPtr, count, 0))
{
throw new CryptographicException(Marshal.GetLastWin32Error());
}
}
}
}
internal static extern bool CryptHashData(
SafeCryptoHashHandle hash,
IntPtr plainText,
int length,
int flags);
internal static extern bool CryptGetHashParam(
SafeCryptoHashHandle hash,
HashParameter hashParameter,
[Out, MarshalAs(UnmanagedType.LPArray)] byte[] hashValue,
[In, Out] ref int length,
int flags);
internal static extern bool CryptCreateHash(
SafeCryptoContextHandle cryptoContext,
AlgorithmId algorithmId,
SafeCryptoKeyHandle key,
int flags,
out SafeCryptoHashHandle hash);