Circumventing Barnes & Noble DRM for EPUB

In a move sure to leave consumers scratching their heads (especially the ones already wondering why they bought a Nook), Barnes & Noble has decided to implement their own DRM scheme for EPUB books. They partnered with Adobe to do it (it’s a variant of their ADEPT scheme), and all the Adobe SDK users will get access to it eventually. But for now much hilarity ensues as consumers buy books they can’t read on their devices.

The basic idea behind the B&N EPUB scheme is the same as that used by the ill-fated eReader format B&N acquired – step 1: generate an encryption key from the book-purchaser’s name + credit card #; step 2: hope that they don’t like giving that information out to strangers. They like to call this a form of “social DRM,” although I believe a more appropriate term is “silly.”

It would be very bad form for an application to keep user CC#s just sitting around on disk, so the Windows version of the Barnes & Noble Desktop Reader application (BDReader) just holds on to the generated key and not the source info. A wise decision, for which I congratulate them. It then stores this key in plain text in a sqlite3 database. An... interesting... decision, for which I thank them. Update: and then it turned out the key-generation algorithm was pretty easy too...

So now three scripts:

A Windows-only key-retrieval script: ignoblekey (version 2)

An any-platform key-generation script: ignoblekeygen (version 1)

And an any-platform book-decryption script: ignobleepub (version 1)

You need the decryption script and one of either the key-retrieval or key-generation scripts. They produce the same output, and the key-generator works on any platform, but I released the Windows key-retrieval script first and will leave it up for Windows users who’d rather not give their credit card number to random programs they download off the Internet (despite being a source-visible script and all).

For good only, please.