public static RSA GetRSAPublicKey(this X509Certificate2 certificate)
{
if (certificate == null)
{
throw new ArgumentNullException("certificate");
}
if (!IsRSA(certificate))
{
return(null);
}
PublicKey publicKey = certificate.PublicKey;
AsnEncodedData asn = publicKey.EncodedKeyValue;
IntPtr structType = new IntPtr(CapiNative.CNG_RSA_PUBLIC_KEY_BLOB);
SafeLocalAllocHandle cngBlobHandle;
uint cngBlobLength;
bool result = CapiNative.DecodeObject(structType, asn.RawData, out cngBlobHandle, out cngBlobLength);
if (!result)
{
throw new CryptographicException(Marshal.GetLastWin32Error());
}
byte[] cngBlob = new byte[cngBlobLength];
using (cngBlobHandle)
{
Marshal.Copy(cngBlobHandle.DangerousGetHandle(), cngBlob, 0, cngBlob.Length);
}
CngKey key = CngKey.Import(cngBlob, CngKeyBlobFormat.GenericPublicBlob);
return(new RSACng(key));
}
public static DSA GetDSAPublicKey(this X509Certificate2 certificate)
{
if (certificate == null)
{
throw new ArgumentNullException("certificate");
}
if (!IsDSA(certificate))
{
return(null);
}
unsafe
{
DSAParameters dp = new DSAParameters();
SafeLocalAllocHandle dssKeyLocalAlloc = null;
try
{
byte[] encodedPublicKey = certificate.PublicKey.EncodedKeyValue.RawData;
uint cbDSSKey;
if (!CapiNative.DecodeObject((IntPtr)(CapiNative.X509_DSS_PUBLICKEY), encodedPublicKey, out dssKeyLocalAlloc, out cbDSSKey))
{
throw new CryptographicException(Marshal.GetLastWin32Error());
}
if (cbDSSKey < Marshal.SizeOf(typeof(CapiNative.CRYPTOAPI_BLOB)))
{
throw new CryptographicException();
}
CapiNative.CRYPTOAPI_BLOB *pDssKeyBlob = (CapiNative.CRYPTOAPI_BLOB *)(dssKeyLocalAlloc.DangerousGetHandle());
dp.Y = ToBigEndianByteArray(*pDssKeyBlob);
}
finally
{
if (dssKeyLocalAlloc != null)
{
dssKeyLocalAlloc.Dispose();
dssKeyLocalAlloc = null;
}
}
SafeLocalAllocHandle dssParametersLocalHandle = null;
try
{
byte[] encodedKeyAlgorithmParameters = certificate.GetKeyAlgorithmParameters();
uint cbDSSParams;
if (!CapiNative.DecodeObject((IntPtr)(CapiNative.X509_DSS_PARAMETERS), encodedKeyAlgorithmParameters, out dssParametersLocalHandle, out cbDSSParams))
{
throw new CryptographicException(Marshal.GetLastWin32Error());
}
if (cbDSSParams < Marshal.SizeOf(typeof(CapiNative.CERT_DSS_PARAMETERS)))
{
throw new CryptographicException();
}
CapiNative.CERT_DSS_PARAMETERS *pDssParameters = (CapiNative.CERT_DSS_PARAMETERS *)(dssParametersLocalHandle.DangerousGetHandle());
dp.P = ToBigEndianByteArray(pDssParameters->p);
dp.Q = ToBigEndianByteArray(pDssParameters->q);
dp.G = ToBigEndianByteArray(pDssParameters->g);
}
finally
{
if (dssParametersLocalHandle != null)
{
dssParametersLocalHandle.Dispose();
dssParametersLocalHandle = null;
}
}
DSACng dsaCng = new DSACng();
dsaCng.ImportParameters(dp);
return(dsaCng);
}
}