How To Prevent MP3 Re-encoding?

[Ambisphere]

Some "not so technically informed" people do not seem to understand that re-encoding a MP3 results in a considerable loss of sound quality. This has been going on quite a bit at various P2P networks and is frustrating, in that it is deceptive to other peers who cannot be sure whether a MP3 they are downloading has been re-encoded or not. Does anyone know of a software program that prevents a MP3 from being re-encoded? I am guessing that it would be some sort of encryption program? Thank you.