Dealing with Kindle for PC/Mac 1.19 and KFX in calibre - Page 53

darryl · 06-04-2020, 09:13 PM

Quote:

Originally Posted by pdurrant

There's a pull request at Alf's github. I haven't tried it yet (you'd need to get the new source and integrate it into the plugin).

Thanks Paul. If I do this I will of course report the results.

Iris-maybe · 06-05-2020, 05:15 AM

I just check the pull requests, there is no source code about new kindle kfx. I would like to test it. Can you please share the link here?

pdurrant · 06-05-2020, 05:18 AM

Quote:

Originally Posted by Iris-maybe

I just check the pull requests, there is no source code about new kindle kfx. I would like to test it. Can you please share the link here?

The problem is, I beleive, new encryption of the master key for ebook encryption. Nothing to do with KFX itself, which is handled by a separate import plugin that handles DRM-free KFX files.

JSWolf · 06-05-2020, 05:18 AM

Quote:

Originally Posted by Iris-maybe

I just check the pull requests, there is no source code about new kindle kfx. I would like to test it. Can you please share the link here?

It's not for KFX. It's to get the key from newer Kindle apps and use it to remove the DRM from Mobi and KF8.

Iris-maybe · 06-05-2020, 05:26 AM

Not all kfx ebooks encrypted.

lkmiller · 06-05-2020, 08:17 AM

Quote:

Originally Posted by Iris-maybe

I just check the pull requests, there is no source code about new kindle kfx. I would like to test it. Can you please share the link here?

It's a pull request at Apprentice Harper's GitHub repository. Haven't tried it myself. I haven't updated from Kindle for PC 1.17 yet. So I can go on pretending KFX format doesn't exist for as long as I possibly can...maybe longer.

pdurrant · 06-05-2020, 09:26 AM

Quote:

Originally Posted by lkmiller

So I can go on pretending KFX format doesn't exist for as long as I possibly can...maybe longer.

Me too.

But I might have to move to Catalina soon, so I hope it works for Macs and PCs.

darryl · 06-05-2020, 09:33 AM

As I understand it the pull request referred to is entitled "Finish .kinf2018 support". I had a quick look but haven't downloaded it as yet. The commit has a link to the apprenticesakuya github which is one commit ahead, presumably this one. What I intend to do if I get the chance is to clone the apprentice sakuya repository using git on Linux. I haven't worked with the tools before and my expertise is limited, but it looks like it may be as simple as running the make_release.py script to create the plugin zip file. I'm not sure where we currently are with decryption of kfx with or without drm.

pdurrant · 06-05-2020, 09:48 AM

Quote:

Originally Posted by darryl

As I understand it the pull request referred to is entitled "Finish .kinf2018 support". I had a quick look but haven't downloaded it as yet. The commit has a link to the apprenticesakuya github which is one commit ahead, presumably this one. What I intend to do if I get the chance is to clone the apprentice sakuya repository using git on Linux. I haven't worked with the tools before and my expertise is limited, but it looks like it may be as simple as running the make_release.py script to create the plugin zip file. I'm not sure where we currently are with decryption of kfx with or without drm.

Any plugin is just a zip of all the files for the plugin. A script might be overkill.

AFAIUI, the current tool will remove DRM from KFX files, and then the KFX input plugin will decode the KFX file.

jhowell · 06-05-2020, 01:36 PM

Amazon has made two separate DRM changes that are not yet handled by the current version of the DRM Tools.

Kindle for PC and Mac versions 1.25 and later store the encryption key needed to decode books in a file named ".kinf2018", which is protected using a new encryption scheme. It appears that a solution for this has been found for the PC app. It is not yet known whether it can also be applied to Kindle for Mac.

Kindle for PC/Mac 1.25 and e-ink Kindle firmware 5.10.2 and later also include a new DRM scheme for books in KFX format. Even if the main key can be recovered from .kinf2018 files the question still remains of how to use it to decode the new KFX DRM. No one has reported any progress on this as far as I know.

darryl · 06-05-2020, 06:45 PM

Quote:

Originally Posted by jhowell

Amazon has made two separate DRM changes that are not yet handled by the current version of the DRM Tools.

Kindle for PC and Mac versions 1.25 and later store the encryption key needed to decode books in a file named ".kinf2018", which is protected using a new encryption scheme. It appears that a solution for this has been found for the PC app. It is not yet known whether it can also be applied to Kindle for Mac.

Kindle for PC/Mac 1.25 and e-ink Kindle firmware 5.10.2 and later also include a new DRM scheme for books in KFX format. Even if the main key can be recovered from .kinf2018 files the question still remains of how to use it to decode the new KFX DRM. No one has reported any progress on this as far as I know.

Thanks for updating us with the current position

darryl · 06-05-2020, 10:24 PM

I tested the new code with K4PC 1.28.0 on Windows 10. Unlike the current version there is a delay in retrieving the default key which is different to and longer than what is retrieved by the current version. It may well be the correct key. However, there is no easy way for me to test this. I tried importing a Baen book, Tom Kratman's A Pillow of Fire by Night, which resulted in a kfx_zip file apparently encumbered by DRM. The renderer trick does not work with this version so it seems K4PC will not download an old kf8 file. To summarise, whilst there is some indication the correct key may actually be retrieved it seems the plugin cannot currently decrypt a kfx format book with no further drm over and above the default kfx encryption.

odamizu · 06-06-2020, 01:21 AM

Well, I just did a quick test with K4Mac 1.26.1, on which you can disable renderer-test to get KF8. While kinf2018 was found, it could not be decrypted. I tried it on both KF8 and KFX. However, my skills in this area are pretty sparse, so there's a good chance I missed something.

darryl · 06-06-2020, 03:35 AM

Quote:

Originally Posted by odamizu

Well, I just did a quick test with K4Mac 1.26.1, on which you can disable renderer-test to get KF8. While kinf2018 was found, it could not be decrypted. I tried it on both KF8 and KFX. However, my skills in this area are pretty sparse, so there's a good chance I missed something.

My skills in this area are also rudimentary. jhowell said a few posts ago:

Quote:

.... if the main key can be recovered from .kinf2018 files the question still remains of how to use it to decode the new KFX DRM.

I suspect this may be the problem. The key may well be correct, but the decryption algorithm does not work with the new scheme, even with the correct key. It is interesting that it also fails to decrypt kf8. Perhaps the changes affected more than just kfx.

odamizu · 06-07-2020, 12:20 AM

Quote:

Originally Posted by jhowell

... if the main key can be recovered from .kinf2018 files the question still remains of how to use it to decode the new KFX DRM. No one has reported any progress on this as far as I know.

Quote:

Originally Posted by darryl

I suspect this may be the problem. The key may well be correct, but the decryption algorithm does not work with the new scheme, even with the correct key. It is interesting that it also fails to decrypt kf8. Perhaps the changes affected more than just kfx.

Actually, I suspect the problem in my test is that I don't know what I'm doing and didn't integrate the new code properly

In any case, it was a quick test. When I have more time I will dig deeper and try again.

06-05-2020, 09:33 AM	#788
darryl Wizard Posts: 3,108 Karma: 60231510 Join Date: Nov 2011 Location: Australia Device: Kobo Aura H2O, Kindle Oasis, Huwei Ascend Mate 7	As I understand it the pull request referred to is entitled "Finish .kinf2018 support". I had a quick look but haven't downloaded it as yet. The commit has a link to the apprenticesakuya github which is one commit ahead, presumably this one. What I intend to do if I get the chance is to clone the apprentice sakuya repository using git on Linux. I haven't worked with the tools before and my expertise is limited, but it looks like it may be as simple as running the make_release.py script to create the plugin zip file. I'm not sure where we currently are with decryption of kfx with or without drm. Last edited by darryl; 06-05-2020 at 09:35 AM.

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06-05-2020, 05:15 AM	#782
Iris-maybe Member Posts: 23 Karma: 10 Join Date: Sep 2017 Device: kindle paperwhite2	I just check the pull requests, there is no source code about new kindle kfx. I would like to test it. Can you please share the link here?

06-05-2020, 05:26 AM	#785
Iris-maybe Member Posts: 23 Karma: 10 Join Date: Sep 2017 Device: kindle paperwhite2	Not all kfx ebooks encrypted.

06-05-2020, 01:36 PM	#790
jhowell Grand Sorcerer Posts: 6,495 Karma: 84420419 Join Date: Nov 2011 Location: Tampa Bay, Florida Device: Kindles	Amazon has made two separate DRM changes that are not yet handled by the current version of the DRM Tools. Kindle for PC and Mac versions 1.25 and later store the encryption key needed to decode books in a file named ".kinf2018", which is protected using a new encryption scheme. It appears that a solution for this has been found for the PC app. It is not yet known whether it can also be applied to Kindle for Mac. Kindle for PC/Mac 1.25 and e-ink Kindle firmware 5.10.2 and later also include a new DRM scheme for books in KFX format. Even if the main key can be recovered from .kinf2018 files the question still remains of how to use it to decode the new KFX DRM. No one has reported any progress on this as far as I know.

06-05-2020, 10:24 PM	#792
darryl Wizard Posts: 3,108 Karma: 60231510 Join Date: Nov 2011 Location: Australia Device: Kobo Aura H2O, Kindle Oasis, Huwei Ascend Mate 7	I tested the new code with K4PC 1.28.0 on Windows 10. Unlike the current version there is a delay in retrieving the default key which is different to and longer than what is retrieved by the current version. It may well be the correct key. However, there is no easy way for me to test this. I tried importing a Baen book, Tom Kratman's A Pillow of Fire by Night, which resulted in a kfx_zip file apparently encumbered by DRM. The renderer trick does not work with this version so it seems K4PC will not download an old kf8 file. To summarise, whilst there is some indication the correct key may actually be retrieved it seems the plugin cannot currently decrypt a kfx format book with no further drm over and above the default kfx encryption.

06-06-2020, 01:21 AM	#793
odamizu just an egg Posts: 1,585 Karma: 4300000 Join Date: Mar 2015 Device: Kindle, iOS	Well, I just did a quick test with K4Mac 1.26.1, on which you can disable renderer-test to get KF8. While kinf2018 was found, it could not be decrypted. I tried it on both KF8 and KFX. However, my skills in this area are pretty sparse, so there's a good chance I missed something.

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