Dealing with Kindle for PC/Mac 1.19 and KFX in calibre - Page 55

darryl · 06-16-2020, 01:00 AM

Quote:

Originally Posted by odamizu

apprenticesakuya has added another commit on GitHub: "Support KFX VoucherEnvelope versions 2 and 3"

This commit is ion.py rather than kindlekey.py

I will test later on Windows 10. After the previous commit it was apparently finding the correct key but failing to decrypt the voucher. This looks very promising.

darryl · 06-16-2020, 01:58 AM

Very good news everyone. Thanks to Apprentice Sakuya, whoever you are. His latest commit seems to solve the problem with decrypting Amazon books. I was able to successfully decrypt both a Public Domain kfx book and a book officially protected by DRM. All using the Kindle App version 1.28.0 on Windows 10. This results in the import to Calibre of a .kfx file (not a kfx-zip). The Calibre viewer cannot read the kfx file, but the file can be converted to another format (I tried .azw3 and epub) which the viewer of course will read.

Be aware that the tools on Apprentice Harper's github have, at the time of posing, not been updated to include Apprentice Sakuya's commits. There will no doubt be a new version released soon.

Please remember that kfx is not the best format to convert from, for reasons which have been discussed on Mobileread in the past. The results in relation to the books I tested seem to be fine on a cursory examination.

Once again thanks to Apprentice Sakuya. I look forward to others reporting on their results.

darryl · 06-16-2020, 04:57 AM

Further test. Also works with decrypting kfx from e-ink Kindle.

Sirtel · 06-16-2020, 10:24 AM

Yay! Many-many thanks to Apprentice Sakuya and the testers here on MR!

Still, I'm going to stick to my old Kindle for PC 1.17 for as long as I can. Just in case...

jhowell · 06-16-2020, 10:43 AM

Quote:

Originally Posted by darryl

Once again thanks to Apprentice Sakuya. I look forward to others reporting on their results.

I tried it on a book in KFX format downloaded using Kindle for PC version 1.28 and it worked for me.

I am curious to see how long it takes Amazon to react to this. They appear to be taking the integrity of KFX DRM seriously.

darryl · 06-16-2020, 07:44 PM

Quote:

Originally Posted by jhowell

I tried it on a book in KFX format downloaded using Kindle for PC version 1.28 and it worked for me.

I am curious to see how long it takes Amazon to react to this. They appear to be taking the integrity of KFX DRM seriously.

I fear that may well be the case. In which case we will likely have the usual arms-race type scenario with long periods where Amazon DRM cannot be decrypted. I believe this would result in some loss of sales to Amazon, though unfortunately I think only a tiny minority care about DRM, making these minimal. Though who knows. We do tend to read a lot of books.

Interestingly enough, if Amazon is now taking DRM more seriously, what has prompted them to do so? I doubt the large publishers are able to exert significant influence in this regard, even assuming they wanted to. Amazon does seem to have excellent data and I would presume any such policy is data driven. Or perhaps it is simply an experiment.

I'll watch what happens with interest.

jhowell · 06-16-2020, 08:39 PM

Quote:

Originally Posted by darryl

Interestingly enough, if Amazon is now taking DRM more seriously, what has prompted them to do so?

It does not seem to me that they are taking DRM more seriously in general, only for the Kindle for PC/Mac apps and for KFX format.

Amazon wants to keep readers in the Kindle ecosystem. The PC/Mac apps are the main method by which non-Kindle owners remove DRM so there is some logic to keeping those somewhat locked down. Not blocking access by older versions of those apps hints that they are satisfied with the results of just putting a few roadblocks in the way of the DRM removal process.

For KFX DRM it may be a case of them fixing what they can at minimal cost. KFX is still under active development and so it is easy for them to make changes to that DRM. The other formats are frozen and may not be so easily modified.

Quote:

Originally Posted by darryl

I doubt the large publishers are able to exert significant influence in this regard, even assuming they wanted to.

I see one exception to this. There are expensive textbooks published by Pearson Education that until now were only available in apps/devices with secure DRM. I wonder whether Amazon has promised to maintain that situation. If so then this DeDRM change will provoke a quick reaction.

darryl · 06-16-2020, 10:36 PM

Quote:

Originally Posted by jhowell

I see one exception to this. There are expensive textbooks published by Pearson Education that until now were only available in apps/devices with secure DRM. I wonder whether Amazon has promised to maintain that situation. If so then this DeDRM change will provoke a quick reaction.

I hadn't thought about Pearson. Educational publishing continues to be a real blot on the landscape for many reasons. As you say, a quick reaction by Amazon will somewhat clarify the situation. On the other hand, a much slower reaction or none at all would also be instructive so far as Amazon's attitude to its drm is concerned.

JSWolf · 06-17-2020, 10:03 AM

In firmware 5.12.5, did Amazon make any changes to the DRM for KFX?

jhowell · 06-17-2020, 01:49 PM

Quote:

Originally Posted by JSWolf

In firmware 5.12.5, did Amazon make any changes to the DRM for KFX?

Not as far as I can tell.

apprenticeharper · 06-18-2020, 03:32 AM

Apprentice Sakuya's changes are included in release 6.8.0, now available at my github repository.

Harper.

pdurrant · 06-18-2020, 09:55 AM

I'm still on Kindle for Mac 1.17, so all I can say is that it doesn't seem to have broken AZE3 import.

jhowell · 06-19-2020, 03:12 PM

Quote:

Originally Posted by darryl

I was able to successfully decrypt both a Public Domain kfx book and a book officially protected by DRM. All using the Kindle App version 1.28.0 on Windows 10.

Something odd is happening for me today. Could you (or anyone else) try this again on a freshly downloaded book?

bkennelly · 06-19-2020, 04:15 PM

Quote:

Originally Posted by jhowell

Something odd is happening for me today. Could you (or anyone else) try this again on a freshly downloaded book?

All KFX books are coming through as KFX-ZIP today, after working yesterday. Amazon probably pushed a change to the key format in response to the release.

jhowell · 06-19-2020, 04:19 PM

Quote:

Originally Posted by bkennelly

All KFX books are coming through as KFX-ZIP today, after working yesterday. Amazon probably pushed a change to the key format in response to the release.

I was afraid of that.

I guess this answers the question of how serious Amazon is about maintaining the security of KFX DRM.

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06-16-2020, 01:58 AM	#812
darryl Wizard Posts: 3,108 Karma: 60231510 Join Date: Nov 2011 Location: Australia Device: Kobo Aura H2O, Kindle Oasis, Huwei Ascend Mate 7	Very good news everyone. Thanks to Apprentice Sakuya, whoever you are. His latest commit seems to solve the problem with decrypting Amazon books. I was able to successfully decrypt both a Public Domain kfx book and a book officially protected by DRM. All using the Kindle App version 1.28.0 on Windows 10. This results in the import to Calibre of a .kfx file (not a kfx-zip). The Calibre viewer cannot read the kfx file, but the file can be converted to another format (I tried .azw3 and epub) which the viewer of course will read. Be aware that the tools on Apprentice Harper's github have, at the time of posing, not been updated to include Apprentice Sakuya's commits. There will no doubt be a new version released soon. Please remember that kfx is not the best format to convert from, for reasons which have been discussed on Mobileread in the past. The results in relation to the books I tested seem to be fine on a cursory examination. Once again thanks to Apprentice Sakuya. I look forward to others reporting on their results.

06-16-2020, 04:57 AM	#813
darryl Wizard Posts: 3,108 Karma: 60231510 Join Date: Nov 2011 Location: Australia Device: Kobo Aura H2O, Kindle Oasis, Huwei Ascend Mate 7	Further test. Also works with decrypting kfx from e-ink Kindle.

06-16-2020, 10:24 AM	#814
Sirtel Grand Sorcerer Posts: 13,499 Karma: 240000001 Join Date: Jan 2014 Location: Estonia Device: Kobo Sage & Libra 2	Yay! Many-many thanks to Apprentice Sakuya and the testers here on MR! Still, I'm going to stick to my old Kindle for PC 1.17 for as long as I can. Just in case...

06-17-2020, 10:03 AM	#819
JSWolf Resident Curmudgeon Posts: 79,792 Karma: 146391129 Join Date: Nov 2006 Location: Roslindale, Massachusetts Device: Kobo Libra 2, Kobo Aura H2O, PRS-650, PRS-T1, nook STR, PW3	In firmware 5.12.5, did Amazon make any changes to the DRM for KFX?

06-18-2020, 03:32 AM	#821
apprenticeharper Apprentices Against DRM Posts: 46 Karma: 9787852 Join Date: Feb 2015 Location: UK Device: Asus Laptop	Apprentice Sakuya's changes are included in release 6.8.0, now available at my github repository. Harper.

06-18-2020, 09:55 AM	#822
pdurrant The Grand Mouse 高貴的老鼠 Posts: 73,989 Karma: 315160596 Join Date: Jul 2007 Location: Norfolk, England Device: Kindle Oasis	I'm still on Kindle for Mac 1.17, so all I can say is that it doesn't seem to have broken AZE3 import.

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