[mattmc]

Originally Posted by jhowell

I have intentionally stayed away from examining the details of encrypted KFX files. As can be seen in the first post in this thread, even "Simultaneous Device Usage: Unlimited" books contain strings like "amzn1.drm-key.v1" and I don't see Amazon calling these books "DRM-Free" anywhere. I don't want to be put in a position of having to defend against an accusation of DMCA violation so I am going to avoid reverse engineering this aspect of KFX. (But I will be happy if someone else does so.)

Interesting. So, because all of the files are "DRMed", even if they are not locked to a particular user or device, it would be a violation of...copyright?...to crack them open? I admit I'm not familiar with DMCA and how it applies to DRM and so on. I thought the reason why de-DRMing software can legally exist is because it is "pitched" as being for users who want to convert their purchased book into a different format, to read on another device or something. Like the way BitTorrent is for "sharing files", even if it gets used for piracy.

Anyway, you make a good point; I don't particularly want to be targeted by Amazon.

Originally Posted by kovidgoyal

Guys, can we please restrict this thread to the KFX format...

Originally Posted by DiapDealer

...we need to reserve this space for discussion about the technical specifications concerning the KFX format.

Agreed. Although, I do think that @AaronShep's data on the new JPEG XR image format is relevant.

Originally Posted by odamizu

I'm the first to admit I know next to nothing about this, but given the findings by james194zt with regard to AES/CBC/PKCS5 encryption with SHA2 256Kb hashes, is cracking KFX even possible at this time? Or is it a waiting game until Amazon releases (if they release) a KFX-capable Kindle for PC/Mac app or kfxgen utility?

In my estimation, yes, we wait for one of those two outcomes. Obviously it would be best if Amazon just gave us the kfxgen utility. That would solve my particular problem of proofing.

A thought did occur to me: since Kindles are basically lightweight Linux machines, could you SSH into one from your desktop and attach GDB to whatever process is reading the files? Kinda a question for the crazy hackers over in the Kindle Developers' Corner.