public unsafe void SignHash()
{
using (var provider = NCryptOpenStorageProvider(KeyStorageProviders.MS_KEY_STORAGE_PROVIDER))
{
using (var keyPair = NCryptCreatePersistedKey(provider, BCrypt.AlgorithmIdentifiers.BCRYPT_RSA_ALGORITHM))
{
int keySize = GetMinimumKeySize(keyPair);
NCryptSetProperty(keyPair, KeyStoragePropertyIdentifiers.NCRYPT_LENGTH_PROPERTY, keySize);
NCryptFinalizeKey(keyPair).ThrowOnError();
byte[] hashData = SHA1.Create().ComputeHash(new byte[] { 0x1 });
var flags = NCryptSignHashFlags.BCRYPT_PAD_PKCS1;
fixed(char *pAlgorithm = BCrypt.AlgorithmIdentifiers.BCRYPT_SHA1_ALGORITHM.ToCharArrayWithNullTerminator())
{
var paddingInfo = new BCrypt.BCRYPT_PKCS1_PADDING_INFO()
{
pszAlgId = pAlgorithm,
};
byte[] signature = NCryptSignHash(keyPair, &paddingInfo, hashData, flags).ToArray();
bool valid = NCryptVerifySignature(keyPair, &paddingInfo, hashData, signature, flags);
Assert.True(valid);
signature[0] = unchecked ((byte)(signature[0] + 1));
valid = NCryptVerifySignature(keyPair, &paddingInfo, hashData, signature, flags);
Assert.False(valid);
}
}
}
}
/// <summary>
/// Performs a signing or verification operation.
/// </summary>
/// <param name="action">The delegate that will actually perform the cryptographic operation.</param>
/// <remarks>
/// This method should not throw an error when verifying a signature and
/// the signature is invalid. Rather, the delegate should retain the result of
/// verification and the caller of this method should share that closure and
/// return the result.
/// </remarks>
protected unsafe void SignOrVerify(SignOrVerifyAction action)
{
Requires.NotNull(action, nameof(action));
if (this.SignaturePadding.Value == AsymmetricSignaturePadding.None)
{
action(null, NCryptSignHashFlags.None);
}
else
{
char[] hashAlgorithmName = HashAlgorithmProviderFactory.GetHashAlgorithmName(this.SignatureHash.Value).ToCharArrayWithNullTerminator();
fixed(char *hashAlgorithmNamePointer = &hashAlgorithmName[0])
{
switch (this.SignaturePadding.Value)
{
case AsymmetricSignaturePadding.Pkcs1:
var pkcs1PaddingInfo = new BCrypt.BCRYPT_PKCS1_PADDING_INFO
{
pszAlgId = hashAlgorithmNamePointer,
};
action(&pkcs1PaddingInfo, NCryptSignHashFlags.BCRYPT_PAD_PKCS1);
break;
case AsymmetricSignaturePadding.Pss:
var pssPaddingInfo = new BCrypt.BCRYPT_PSS_PADDING_INFO
{
pszAlgId = hashAlgorithmNamePointer,
cbSalt = hashAlgorithmName.Length,
};
action(&pssPaddingInfo, NCryptSignHashFlags.BCRYPT_PAD_PSS);
break;
default:
throw new NotImplementedException();
}
}
}
}
