People have been trying to bypass tezfile's and k2s' system for a long time. It doesn't work, siterips makes all of it's money off tezfiles, so they're pretty interested in trying to make it secure. The best way is to find the name of the file(usually its the name of the links for siterips), and just type it in Google, you'll usually see results that link to hosts like vidoza that let you download the whole thing