PlatformNotSupportedException After Upgrading to 2022.1.a13

Recently I upgraded my project from 2019 -> 2022 without many issues, however I am hitting a problem when using System.Security.Cryptography.ProtectedData.Unprotect()

It's throwing a PlatformNotSupportedException stating Operation is not supported on this platform. This should not be the case, as my platform is set to Win64, with the scripting API compat level set to.NET Framework.

 

If it is intended to be unavailable, you can try installing it from NuGet. Is not part of .NET 2.1. The .NET Framework target should contain a Framework 4.8 + .NET Standard 2.1.

https://www.nuget.org/packages/System.Security.Cryptography.ProtectedData/

 

That package depends on System.Security to provide the ProtectedData class, and does not actually contain it.
I have references System.Security previously on 2019 using the csc.rsp file, but since upgrading to 2022 I get the PlatformNotSupportedException despite being on the same platform

I think that support for it has just been removed from the engine somehow. I may need to investigate other solutions as my project currently requires this functionality

 

You're seeing this in the Editor on Windows? Did you try it in a build?

Unity has upgraded mono in 2021.2 and this has changed a lot in how the class libraries are implemented. In case of ProtectedData, the old mono Unity used contained both Windows and Unix implementations in the same dll. But with the effort to merge .Net class library sources, mono now only contains the Unix implementation and uses the CoreFX implementation for Windows.

Which means there are now two different builds of

System.Security.dll

, one that works only on Unix and one that works only on Windows – before the same dll would work on both.

I don't think the platform you select in the Unity editor has an influence on which dll is chosen, the editor has to use the dll for the platform it's running on. But if you're getting a PlatformNotSupportedException, it appears Unity is using the mono code and not the code from CoreFX.

Checking the dlls at

MonoBleedingEdge/lib/mono

, Unity 2021.2 (I don't have 2022.1 installed to check right now) does contain different versions for Windows, Linux and macOS. But the dll at

unityjit-win32/System.Security.dll

contains the Unix and not the Windows code, while the dlls at

unityaot-win32/System.Security.dll

and

net_4_x-win32/System.Security.dll

do contain the Windows code.

Unity ships 29 different

System.Security.dll

and I'm not sure which one is used when. Switching API Compatibility Level or doing a build could get you a different dll and make ProtectedData work. But it's probably good to submit a bug either way.

 

I was able to get it working in both Editor and a dedicated server build.
I had to grab a System.Security.dll from

"C:\Program Files\Unity\Hub\Editor\2022.2.14f1\Editor\Data\MonoBleedingEdge\lib\mono\unityjit-win32\System.Security.dll"

and place it in the Assets folder, and set my build target to 32bit

I dn't know if this is a good one to use, or what problems might occur in t he future, but it does let me Unprotect() data.