[Unity-Windows-Build] Cannot find type 'X' in module 'Y'

I am building a project for Windows Phone (8.1) in Unity. I have installed Windows SDK 8.1, MS VS 2013 and I have required .NET frameworks installed in my Windows 8.1 Laptop.

When I build the project in Unity, it gives me VS .sln project. I opened it in VS 2013 and tried to build it. But, I am getting a error i.e.

Cannot find type System.Security.Cryptography.SymmetricAlgorithm in module mscorlib.dll

I have read posts about this kind of error and those didn't serve my purpose because I didn't import the mentioned namespace in the error in anywhere of the Unity Project. I searched in the plugins too.

I also changed the target framework in MonoDevelop to 4.5. I am using Unity 5.3 and MonoDevelop as IDE.

Any Help is highly appreciated.

 

@karl.jones Can I have your or your any known person's concern about my problem?

 

Isn't mscorlib.dll not available on Windows Phone? Instead of System.Security.Cryptography, generally for Windows Phone we need to use Windows.Security.Cryptography instead.

EDIT: Ah so you say you haven't used this namespace, and that you have checked your plugins. My guess is that there's still a plugin that uses this namespace somewhere... I'm not sure how to check plugins besides ripping half of them out at a time (requires writing stubs a lot of the time) and checking to see if the error disappears.

 

Thank You for your information. The namespace must be in my project. Point is : I have to find it where it is and replace it with Windows.Security.Cryptography. Am I right?

 

Dear karl.jones, thank you for your reply. The answer in the post (given link) is not clear to me. I didn't understand anything. Sorry if you find my query novice

 

I my experience, yes that is how I would proceed. Just know that Windows.Security has a different API than System.Security!