/// <summary>
/// Method take BCrypt handle as input and returns the CNGKey
/// </summary>
/// <param name="bcryptKeyHandle">Accepts BCrypt Handle</param>
/// <returns>Returns CNG key with NCrypt Handle</returns>
private static CngKey LegacyBCryptHandleToNCryptHandle(SafeBCryptKeyHandle bcryptKeyHandle)
{
byte[] keyBlob = BCryptNative.ExportBCryptKey(bcryptKeyHandle, BCryptNative.BCRYPT_ECCPUBLIC_BLOB);
//Now Import the key blob as NCRYPT_KEY_HANDLE
CngKey Key = CngKey.Import(keyBlob, CngKeyBlobFormat.EccPublicBlob);
return(Key);
}
public static ECDsa GetECDsaPublicKey(this X509Certificate2 certificate)
{
if (LocalAppContextSwitches.UseLegacyPublicKeyBehavior)
{
return(LegacyGetECDsaPublicKey(certificate));
}
if (certificate == null)
{
throw new ArgumentNullException("certificate");
}
if (!IsECDsa(certificate))
{
return(null);
}
using (SafeCertContextHandle safeCertContext = X509Native.GetCertificateContext(certificate))
using (SafeBCryptKeyHandle bcryptKeyHandle = ImportPublicKeyInfo(safeCertContext))
{
if (bcryptKeyHandle.IsInvalid)
{
throw new CryptographicException("SR.GetString(SR.Cryptography_OpenInvalidHandle)");
}
string curveName = GetCurveName(bcryptKeyHandle);
if (curveName == null)
{
CngKeyBlobFormat blobFormat = HasExplicitParameters(bcryptKeyHandle) ?
CngKeyBlobFormat.EccFullPublicBlob : CngKeyBlobFormat.EccPublicBlob;
byte[] keyBlob = BCryptNative.ExportBCryptKey(bcryptKeyHandle, blobFormat.Format);
using (CngKey key = CngKey.Import(keyBlob, blobFormat))
{
return(new ECDsaCng(key));
}
}
else
{
CngKeyBlobFormat blobFormat = CngKeyBlobFormat.EccPublicBlob;
byte[] keyBlob = BCryptNative.ExportBCryptKey(bcryptKeyHandle, blobFormat.Format);
ECParameters ecparams = new ECParameters();
ExportNamedCurveParameters(ref ecparams, keyBlob, false);
ecparams.Curve = ECCurve.CreateFromFriendlyName(curveName);
ECDsaCng ecdsa = new ECDsaCng();
ecdsa.ImportParameters(ecparams);
return(ecdsa);
}
}
}