Sure, having no central point sounds like the better think to have, but then how do you provide authenticity ? That's the main problem you're going to face if i

Sure, having no central point sounds like the better think to have, but then how do you provide authenticity ? That's the main problem you're going to face if it starts being popular. You need either trusted sources that can provide you with the correct infohash/pgp signature/whatever, which are the easiest thing to do, or you need some kind of p2p consensus system in which peers "vote" in some way so you can be fairly certain of authenticity. Tribler has made a lot things in this domain, maybe you should check it out.