Good question. It might be considered a derivative work, but I think that would be a new interpretation of that phrase. Big-picture answer is that most people w

Good question. It might be considered a derivative work, but I think that would be a new interpretation of that phrase. Big-picture answer is that most people who write and interpret laws do not know what SHA-1 is, so current laws might not cover TPB with respect to copyright law. It might also be that technology makes some laws silly or at least much harder to enforce, and copyright laws might be one such example. IANAL, but here's one argument against TPB: a checksum of a "controlled file" seems to me akin to the code name of a "controlled substance". If a guy tells you that if you want heroin, you should ask around for "wombats", and then you go ask around for "wombats" and buy some heroin, did the dude that told you the code name do something illegal? Now what if he was just a robot that repeated what he heard, and gathered reviews? "I heard heroin is called wombat, and 100 people are happy with that information". TPB does a little more than that (monitor the number of seeders / leechers, which is integral to prevent fake torrents being submitted), and makes quite a pretty penny off of their services, as well.