Encrypting connectionstrings in Class Library's app.config file

I've written code to encrypt connectionstrings in a web.config and I've seen code that encrypts them in app.config files that are not in Class Library's.  What I can't seem to find, is how (if it's possible) to encrypt connectionstrings in a class library.  Has anyone done this before?  Does anyone know if it is possible?

 Thanks,

James
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