<PackageReference Include="Microsoft.Bcl.Cryptography" Version="10.0.12" />

System.Runtime.Versioning.SupportedOSPlatformGuardAttribute

Annotates a custom guard field, property or method with a supported platform name and optional version. Multiple attributes can be applied to indicate guard for multiple supported platforms.
namespace System.Runtime.Versioning { internal sealed class SupportedOSPlatformGuardAttribute : System.Runtime.Versioning.OSPlatformAttribute { public SupportedOSPlatformGuardAttribute(string platformName); } }