<PackageReference Include="System.Security.Cryptography.Cng" Version="5.0.0-preview.3.20214.6" />

System.Security.Cryptography.CngExportPolicies

public enum CngExportPolicies
namespace System.Security.Cryptography { public enum CngExportPolicies { AllowArchiving = 4, AllowExport = 1, AllowPlaintextArchiving = 8, AllowPlaintextExport = 2, None = 0 } }