[Robotech_Master]

DRM just plain doesn't work. It doesn't do what it's "supposed" to do, because it can be all too easily circumvented. There's no way to keep an encryption scheme from being broken where the recipient is also the attacker, and that's all there is to it.

Concerning e-libraries' DRM, as far as I know it's just bog-standard Mobipocket encryption, of the same kind that locks your book to your up-to-four devices. It's just that they throw in an "expires in X days" restriction as well. Really, it's a rather elegant idea and if it weren't that DRM is totally worthless I'd actually think it was pretty clever.

But anyway, given that the encryption is standard, if you know that a crack works for an "ordinary" Mobi book that you've purchased, in theory there is no reason it shouldn't work for a library book either.

You just have to decide whether your personal code of ethics allows you to crack it (given that even if there is a law against it in your locale as there is in the USA, it's not likely you'll ever be caught unless you go around blabbing about it on public forums), and what said code allows you to do with it.