encryption wouldn't do anything. (note, it is the client that encrypts, such as azureus or utorrent). the way they get you is by joining the torrent and copying down the IPs that come up. if you've ever read a court filing that (and the ISP's logs) are their evidence. encryption won't stop them from getting your IP. (it is useful for confusing your ISP into thinking your traffic might not be torrent)