Resources for Comixology deDRM investigation

[l-l-l-l-l-l]

Using the oldest version of the comixology android app that I could find, I managed to download some comics there. While online I've found people saying that it uses the same encryption as Amazon, what I've found are folders full of extensionless files with the following naming scheme [folder name]-[page number]-[either f or t]. Files ended in "f" are store-grade AES-encrypted zip files, while files ended in "t" should be some sort of key files, though their contents are too long (and their sizes too variable) to be AES keys.

Zipping either the folders, a pair of f/t files or renaming an f file to azw3/epub/zip gives a reading result in calibre of "kfx-zip", but it doesn't remove the drm.

It seems that the first three characters of each t file are ÿ?ÿ while the following 8 characters seem to be the same for all pages of the same book, but change from book to book.

I'll leave here some pairs for the covers and first pages of a couple of books in case someone want to take a chance in finding some way to remove the DRM from them:

library.zip

[ElleKayEm]

If a comic is priced the same (or lower) on Amazon, I buy it there so I can have access to it through Amazon or Comixology. Then you can DeDRM the Amazon copy. For anything else with DRM, I've used this in the past: https://github.com/Cortys/comic-backup

[glmagalhaes]

@ElleKayEm the price part may be true and there is the alternative of getting directly from the browser using a plug-in.

But, the amazon version has a serious compression issue, you can see a lot of artifacts in comics you download, and for some reason, this seems to be restricted to comics, since mangas usually have larger file sizes than comics, even when the majority is just black and white.

and although the browser offer a higher quality to the amazon version, the only way to get the HQ quality is on the app, you would still not be getting the best version available for a color comic, and depending on how the plugin works, you would be limited to your desktop resolution.

And for some reason, comyxology wont offer a app on windows store or a software you can download, making it a hassle to read the best version on the pc, since you need an android emulator to use the app

So, even having those alternatives, removing the drm from the files that you download to the android/apple would be the best option.

[j-howell]

The resolution of comics on Amazon varies significantly based on the device/app to which it is sent. There is a thread on MobileRead from 2018 that discussed this: Some questions regarding Oasis 2 & comics/manga

[glmagalhaes]

I've even used the kindle app on a tablet and you can see compression artifacts on many comics.

[thellamapaul]

@l-l-l-l-l-l Were you able to find a way to read those extensionless files? I'm looking for a way to deDRM my books in the Marvel Comics app which still follows the naming scheme