But if you want a more secure environment while downloading files P2P networks, then Anomos is a simple yet a powerful tool. By default it enables the above mentioned end-to-end protocol encryption, but it even goes further by connecting to PC's at the other-end using an an onion routing method (layer), you know making you an anonymous.
If you don't understand a single word that I said in those paragraphs, then just forget them... if all you need is a well protected Bittorrent client, then I highly recommend Anomos, which can be downloaded for Windows, Mac OSX and GNU Linux as well.
If you use Ubuntu, then all you have to do is to download the appropriate .deb package (below) and simply double click on it would automatically install Anomos in your Ubuntu OS.
For Ubuntu 11.04
For Ubuntu 10.10