Compile assemblies with restrictive access

Is it possible to compile an a开发者_如何学运维ssembly to either: only include certain code parts OR Allow access to certain code based on a credential?

I have an assembly that is redistributed. Certain applications will only use/have access to certain functionality and other will need more.

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You can make internal types accessible for certain assemblies using the System.Runtime.CompilerServices.InternalsVisibleToAttribute. But this attribute's intent is to be used in unit test scenarios.