<PackageReference Include="NETStandard.Library" Version="2.0.0" />

System.Security.Cryptography.X509Certificates.X509ChainPolicy

public sealed class X509ChainPolicy
namespace System.Security.Cryptography.X509Certificates { public static class ECDsaCertificateExtensions { public static ECDsa GetECDsaPrivateKey(this X509Certificate2 certificate); public static ECDsa GetECDsaPublicKey(this X509Certificate2 certificate); } }