<PackageReference Include="System.Security.Cryptography.Cng" Version="5.0.0-preview.2.20160.6" />

System.Security.Cryptography.CngKeyOpenOptions

public enum CngKeyOpenOptions
Specifies options for opening a key.
namespace System.Security.Cryptography { public enum CngKeyOpenOptions { None = 0, UserKey = 0, MachineKey = 32, Silent = 64 } }