Using patent trolling and that DMCA shit would be an easy shortcut to attack Bitcoin...
Attack what part of bitcoin? There is no company running it to sue. It would be like trying to patent bittorrent in an attempt to take down torrent sites. It just wouldn't work. Besides, you have to patent some process or invention that is unique. While the whole bitcoin concept is unique, I don't think it actually has any patentable parts, because it was made from many preexisting technologies.