Decode Signed Request Without Authentication

Question

Are we able to use the Facebook C# SDK to decode the signed_request parameter that is passed to the Facebook Tab page, without using Authentication<

Answer 1

What do you mean 'without authentication'? The signed request is signed with your app secret, so you can decode it regardless of whether the current user has authorised your app

{edit} I now realise you're referring to a library named Authentication{/edit}

If you find another library or reimplement the algorithm for HMAC SHA-256 and a base64url decoder i'm sure you could do it without using that specific library, but it's probably easier to just use it