internal static CngKey Create(ECCurve curve, Func <string, CngAlgorithm> algorithmResolver)
{
System.Diagnostics.Debug.Assert(algorithmResolver != null);
curve.Validate();
CngKeyCreationParameters creationParameters = new CngKeyCreationParameters
{
ExportPolicy = CngExportPolicies.AllowPlaintextExport,
};
CngAlgorithm alg;
if (curve.IsNamed)
{
// Map curve name to algorithm to support pre-Win10 curves
alg = algorithmResolver(curve.Oid.FriendlyName);
if (CngKey.IsECNamedCurve(alg.Algorithm))
{
creationParameters.Parameters.Add(GetPropertyFromNamedCurve(curve));
}
else
{
if (alg == CngAlgorithm.ECDsaP256 || alg == CngAlgorithm.ECDiffieHellmanP256 ||
alg == CngAlgorithm.ECDsaP384 || alg == CngAlgorithm.ECDiffieHellmanP384 ||
alg == CngAlgorithm.ECDsaP521 || alg == CngAlgorithm.ECDiffieHellmanP521)
{
// No parameters required, the algorithm ID has everything built-in.
}
else
{
Debug.Fail(string.Format("Unknown algorithm {0}", alg.ToString()));
throw new ArgumentException(SR.GetString(SR.Cryptography_InvalidKeySize));
}
}
}
else if (curve.IsPrime)
{
byte[] parametersBlob = ECCng.GetPrimeCurveParameterBlob(ref curve);
CngProperty prop = new CngProperty(
KeyPropertyName.ECCParameters,
parametersBlob,
CngPropertyOptions.None);
creationParameters.Parameters.Add(prop);
alg = algorithmResolver(null);
}
else
{
throw new PlatformNotSupportedException(
SR.GetString(SR.Cryptography_CurveNotSupported, curve.CurveType.ToString()));
}
try
{
return(Create(alg, null, creationParameters));
}
catch (CryptographicException e)
{
Interop.NCrypt.ErrorCode errorCode = (Interop.NCrypt.ErrorCode)e.HResult;
if (errorCode == Interop.NCrypt.ErrorCode.NTE_INVALID_PARAMETER ||
errorCode == Interop.NCrypt.ErrorCode.NTE_NOT_SUPPORTED)
{
string target = curve.IsNamed ? curve.Oid.FriendlyName : curve.CurveType.ToString();
throw new PlatformNotSupportedException(SR.GetString(SR.Cryptography_CurveNotSupported, target), e);
}
throw;
}
}
