public static byte[] DeriveKey(CngKey externalPubKey, CngKey privateKey, int keyBitLength, byte[] algorithmId, byte[] partyVInfo, byte[] partyUInfo, byte[] suppPubInfo)
{
uint num;
byte[] numArray;
using (ECDiffieHellmanCng eCDiffieHellmanCng = new ECDiffieHellmanCng(privateKey))
{
using (SafeNCryptSecretHandle safeNCryptSecretHandle = eCDiffieHellmanCng.DeriveSecretAgreementHandle(externalPubKey))
{
using (NCrypt.NCryptBuffer nCryptBuffer = new NCrypt.NCryptBuffer(8, algorithmId))
{
using (NCrypt.NCryptBuffer nCryptBuffer1 = new NCrypt.NCryptBuffer(10, partyVInfo))
{
using (NCrypt.NCryptBuffer nCryptBuffer2 = new NCrypt.NCryptBuffer(9, partyUInfo))
{
using (NCrypt.NCryptBuffer nCryptBuffer3 = new NCrypt.NCryptBuffer(11, suppPubInfo))
{
using (NCrypt.NCryptBufferDesc nCryptBufferDesc = new NCrypt.NCryptBufferDesc(new NCrypt.NCryptBuffer[] { nCryptBuffer, nCryptBuffer1, nCryptBuffer2, nCryptBuffer3 }))
{
uint num1 = NCrypt.NCryptDeriveKey(safeNCryptSecretHandle, "SP800_56A_CONCAT", nCryptBufferDesc, null, 0, out num, 0);
if (num1 != 0)
{
throw new CryptographicException(string.Format("NCrypt.NCryptDeriveKey() failed with status code:{0}", num1));
}
byte[] numArray1 = new byte[num];
num1 = NCrypt.NCryptDeriveKey(safeNCryptSecretHandle, "SP800_56A_CONCAT", nCryptBufferDesc, numArray1, num, out num, 0);
if (num1 != 0)
{
throw new CryptographicException(string.Format("NCrypt.NCryptDeriveKey() failed with status code:{0}", num1));
}
numArray = Arrays.LeftmostBits(numArray1, keyBitLength);
}
}
}
}
}
}
}
return(numArray);
}
public static byte[] DeriveKey(CngKey externalPubKey, CngKey privateKey, int keyBitLength, byte[] algorithmId, byte[] partyVInfo, byte[] partyUInfo, byte[] suppPubInfo)
{
#if NET40 || NET461
using (var cng = new ECDiffieHellmanCng(privateKey))
{
using (SafeNCryptSecretHandle hSecretAgreement = cng.DeriveSecretAgreementHandle(externalPubKey))
{
using (var algIdBuffer = new NCrypt.NCryptBuffer(NCrypt.KDF_ALGORITHMID, algorithmId))
using (var pviBuffer = new NCrypt.NCryptBuffer(NCrypt.KDF_PARTYVINFO, partyVInfo))
using (var pvuBuffer = new NCrypt.NCryptBuffer(NCrypt.KDF_PARTYUINFO, partyUInfo))
using (var spiBuffer = new NCrypt.NCryptBuffer(NCrypt.KDF_SUPPPUBINFO, suppPubInfo))
{
using (var parameters = new NCrypt.NCryptBufferDesc(algIdBuffer, pviBuffer, pvuBuffer, spiBuffer))
{
uint derivedSecretByteSize;
uint status = NCrypt.NCryptDeriveKey(hSecretAgreement, "SP800_56A_CONCAT", parameters, null, 0, out derivedSecretByteSize, 0);
if (status != BCrypt.ERROR_SUCCESS)
{
throw new CryptographicException(string.Format("NCrypt.NCryptDeriveKey() failed with status code:{0}", status));
}
var secretKey = new byte[derivedSecretByteSize];
status = NCrypt.NCryptDeriveKey(hSecretAgreement, "SP800_56A_CONCAT", parameters, secretKey, derivedSecretByteSize, out derivedSecretByteSize, 0);
if (status != BCrypt.ERROR_SUCCESS)
{
throw new CryptographicException(string.Format("NCrypt.NCryptDeriveKey() failed with status code:{0}", status));
}
return(Arrays.LeftmostBits(secretKey, keyBitLength));
}
}
}
}
#elif NETSTANDARD1_4
throw new NotImplementedException("not yet");
#endif
}
public static byte[] DeriveKeyMaterial(
this ECDiffieHellmanCng provider,
ECDiffieHellmanPublicKey otherPartyPublicKey,
byte[] algorithmId,
byte[] partyUInfo,
byte[] partyVInfo)
{
Collection <IntPtr> ResourcesToFree = new Collection <IntPtr>();
try
{
using SafeNCryptSecretHandle Agreement = provider.DeriveSecretAgreementHandle(otherPartyPublicKey);
IntPtr AlgorithmIdPtr = Marshal.AllocHGlobal(algorithmId.Length);
ResourcesToFree.Add(AlgorithmIdPtr);
Marshal.Copy(algorithmId, 0, AlgorithmIdPtr, algorithmId.Length);
IntPtr PartyUPtr = Marshal.AllocHGlobal(partyUInfo.Length);
ResourcesToFree.Add(PartyUPtr);
Marshal.Copy(partyUInfo, 0, PartyUPtr, partyUInfo.Length);
IntPtr PartyVPtr = Marshal.AllocHGlobal(partyVInfo.Length);
ResourcesToFree.Add(PartyVPtr);
Marshal.Copy(partyVInfo, 0, PartyVPtr, partyVInfo.Length);
NativeMethods.NCryptBuffer[] Buffers = new NativeMethods.NCryptBuffer[]
{
new NativeMethods.NCryptBuffer
{
cbBuffer = (uint)algorithmId.Length,
BufferType = NativeMethods.BufferType.KDF_ALGORITHMID,
pvBuffer = AlgorithmIdPtr
},
new NativeMethods.NCryptBuffer
{
cbBuffer = (uint)partyUInfo.Length,
BufferType = NativeMethods.BufferType.KDF_PARTYUINFO,
pvBuffer = PartyUPtr
},
new NativeMethods.NCryptBuffer
{
cbBuffer = (uint)partyVInfo.Length,
BufferType = NativeMethods.BufferType.KDF_PARTYVINFO,
pvBuffer = PartyVPtr
}
};
IntPtr BufferPtr = Marshal.AllocHGlobal(Buffers.Length * Marshal.SizeOf(typeof(NativeMethods.NCryptBuffer)));
ResourcesToFree.Add(BufferPtr);
IntPtr Location = BufferPtr;
for (int i = 0; i < Buffers.Length; i++)
{
Marshal.StructureToPtr(Buffers[i], Location, false);
Location = new IntPtr(Location.ToInt64() + Marshal.SizeOf(typeof(NativeMethods.NCryptBuffer)));
}
NativeMethods.NCryptBufferDesc ParameterList = new NativeMethods.NCryptBufferDesc
{
cBuffers = Buffers.Length,
pBuffers = BufferPtr
};
byte[] DerivedKey = new byte[32];
NativeMethods.ErrorCode ErrorCode = NativeMethods.NCryptDeriveKey(
Agreement,
"SP800_56A_CONCAT",
ref ParameterList,
DerivedKey,
DerivedKey.Length,
out int NumberOfBytesDerived,
0);
if (ErrorCode != NativeMethods.ErrorCode.Success)
{
throw new InvalidOperationException($"KeyMaterial could not be derived. ErrorCode [{ErrorCode}], Win32Error [{Marshal.GetLastWin32Error()}] returned.");
}
if (NumberOfBytesDerived != 32)
{
throw new InvalidOperationException("KeyMaterial size was invalid.");
}
return(DerivedKey);
}
finally
{
foreach (IntPtr Resource in ResourcesToFree)
{
Marshal.FreeHGlobal(Resource);
}
}
}
