private static TAlgorithm DecodeECPublicKey <TAlgorithm>(
CertificatePal certificatePal,
Func <CngKey, TAlgorithm> factory,
Action <TAlgorithm, ECParameters> import,
CryptImportPublicKeyInfoFlags importFlags = CryptImportPublicKeyInfoFlags.NONE)
where TAlgorithm : AsymmetricAlgorithm, new()
{
TAlgorithm key;
using (SafeBCryptKeyHandle bCryptKeyHandle = ImportPublicKeyInfo(certificatePal.CertContext, importFlags))
{
CngKeyBlobFormat blobFormat;
byte[] keyBlob;
string? curveName = GetCurveName(bCryptKeyHandle);
if (curveName == null)
{
if (HasExplicitParameters(bCryptKeyHandle))
{
blobFormat = CngKeyBlobFormat.EccFullPublicBlob;
}
else
{
blobFormat = CngKeyBlobFormat.EccPublicBlob;
}
keyBlob = ExportKeyBlob(bCryptKeyHandle, blobFormat);
using (CngKey cngKey = CngKey.Import(keyBlob, blobFormat))
{
key = factory(cngKey);
}
}
else
{
blobFormat = CngKeyBlobFormat.EccPublicBlob;
keyBlob = ExportKeyBlob(bCryptKeyHandle, blobFormat);
ECParameters ecparams = default;
ExportNamedCurveParameters(ref ecparams, keyBlob, false);
ecparams.Curve = ECCurve.CreateFromFriendlyName(curveName);
key = new TAlgorithm();
import(key, ecparams);
}
}
return(key);
}
private static SafeBCryptKeyHandle ImportPublicKeyInfo(SafeCertContextHandle certContext, CryptImportPublicKeyInfoFlags importFlags)
{
unsafe
{
SafeBCryptKeyHandle bCryptKeyHandle;
bool mustRelease = false;
certContext.DangerousAddRef(ref mustRelease);
try
{
unsafe
{
bool success = Interop.crypt32.CryptImportPublicKeyInfoEx2(Interop.Crypt32.CertEncodingType.X509_ASN_ENCODING, &(certContext.CertContext->pCertInfo->SubjectPublicKeyInfo), importFlags, null, out bCryptKeyHandle);
if (!success)
{
throw Marshal.GetHRForLastWin32Error().ToCryptographicException();
}
return(bCryptKeyHandle);
}
}
finally
{
if (mustRelease)
{
certContext.DangerousRelease();
}
}
}
}
public static unsafe partial bool CryptImportPublicKeyInfoEx2(CertEncodingType dwCertEncodingType, CERT_PUBLIC_KEY_INFO *pInfo, CryptImportPublicKeyInfoFlags dwFlags, void *pvAuxInfo, out SafeBCryptKeyHandle phKey);
