private static byte[] SignHash(byte[] hash, CngKey key, string algorithm, int saltSize)
{
var paddingIndo = new BCrypt.BCRYPT_PSS_PADDING_INFO(algorithm, saltSize);
uint size;
uint status;
status = NCrypt.NCryptSignHash(key.Handle, ref paddingIndo, hash, hash.Length, null, 0, out size, BCrypt.BCRYPT_PAD_PSS);
if (status != BCrypt.ERROR_SUCCESS)
{
throw new CryptographicException(string.Format("NCrypt.NCryptSignHash() (signature size) failed with status code:{0}", status));
}
byte[] signature = new byte[size];
status = NCrypt.NCryptSignHash(key.Handle, ref paddingIndo, hash, hash.Length, signature, signature.Length, out size, BCrypt.BCRYPT_PAD_PSS);
if (status != BCrypt.ERROR_SUCCESS)
{
throw new CryptographicException(string.Format("NCrypt.NCryptSignHash() failed with status code:{0}", status));
}
return(signature);
}
private static bool VerifyHash(byte[] hash, byte[] signature, CngKey key, string algorithm, int saltSize)
{
var paddingInfo = new BCrypt.BCRYPT_PSS_PADDING_INFO(algorithm, saltSize);
uint status = NCrypt.NCryptVerifySignature(key.Handle, ref paddingInfo, hash, hash.Length, signature, signature.Length, BCrypt.BCRYPT_PAD_PSS);
if (status == NCrypt.NTE_BAD_SIGNATURE) //honestly it always failing with NTE_INVALID_PARAMETER, but let's stick to public API
{
return(false);
}
if (status != BCrypt.ERROR_SUCCESS)
{
throw new CryptographicException(string.Format("NCrypt.NCryptSignHash() (signature size) failed with status code:{0}", status));
}
return(true);
}
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[] Decrypt(byte[] cipherText, CngKey key, CngAlgorithm hash)
{
var paddingInfo = new BCrypt.BCRYPT_OAEP_PADDING_INFO(hash.Algorithm);
uint plainTextByteSize;
uint status = NCrypt.NCryptDecrypt(key.Handle, cipherText, cipherText.Length, ref paddingInfo, null, 0, out plainTextByteSize, BCrypt.BCRYPT_PAD_OAEP);
if (status != BCrypt.ERROR_SUCCESS)
{
throw new CryptographicException(string.Format("NCrypt.Decrypt() (plaintext buffer size) failed with status code:{0}", status));
}
var plainText = new byte[plainTextByteSize];
status = NCrypt.NCryptDecrypt(key.Handle, cipherText, cipherText.Length, ref paddingInfo, plainText, plainTextByteSize, out plainTextByteSize, BCrypt.BCRYPT_PAD_OAEP);
if (status != BCrypt.ERROR_SUCCESS)
{
throw new CryptographicException(string.Format("NCrypt.Decrypt() failed with status code:{0}", status));
}
return(plainText);
}