[jeroenhd]

Fair use is such a meme at this point often perpetrated by content creators who want to infringe on copyright (because they disagree with many parts of copyright law) so they claim whatever they're doing is just "fair use".

The authors of this library can't possibly defend themselves by claiming fair use and they damn well know it. The real question is whether the tool really does break encryption or if the tool is just an implementation of the algorithm that doesn't comply with their terms and conditions. Theoretically, a white-room reverse engineered implementation could be written without signing any contract and the terms and conditions would only serve to cut off their access after violation, but you'd probably have a hard time convincing a judge of that. I don't favour their chances in a lawsuit, but as they don't publish any keys, it's clear that they don't really break anything.

There could still be a violation going on if they hold one of those silly American software patents, but that would be solvable by only distributing the tools in countries where these patents can't be enforced. That also wouldn't be covered by a DMCA takedown of course, they'd need to start an actual lawsuit for that.