<PackageReference Include="System.Security.Cryptography.Cng" Version="5.0.0" />

System.Security.Cryptography.CngKeyHandleOpenOptions

public enum CngKeyHandleOpenOptions
Specifies options for opening key handles.
EphemeralKey = 1

The key handle being opened specifies an ephemeral key.

None = 0

The key handle being opened does not specify an ephemeral key.