So I caved and bought some books from Kyobo that were definitely not on thé usual channels and they have them in such a way that you can only read them from the app. So I downloaded them to my phone using the mobile app (the app doesn't support Linux and is basically a Rootkit anyway) and copied the files from Android/data. They're OEBPS by structure but come in regular folders, is it feasible to just zip them and import to Calibre?

Edit: I found a Calibre plugin for the DRM itself, so it's more "How to make this folder a file"

Edit: so you can just zip them up and import as epub BUT the DRM plugin only goes as far as the metadata, the content itself shows up garbled. Don't know how to get around that one...

AFAIK no public DeDRM methods exist for Korean eBook stores. You're sadly on your own. This country fucking sucks.

Would you be able to see if this one's fake or not? I tried it and it got me the metadata but not anything else: https://github.com/leoincedo/KyoboKr

https://www.reddit.com/r/Calibre/comments/kxzlfq/removing_kyobo_drm_fasoo_from_epub/

They use fasoo drm:
https://en.namu.wiki/w/Fasoo DRM

Send me the link for the apk, if they offer free books I will try to remove the DRM. Seems like a fun activity. I am bored.

Can't promise I will succeed though.

If you want to reverse engineer the app yourself use apklab and http toolkit. That is what I use.

That's explicitly metadata-only. No mention of DeDRMing.

Here you go! https://play.google.com/store/apps/details?id=com.kyobo.ebook.common.b2c

Give the name of a free book. Also what an awful app, it is an abomination. Is there a way to change the language to English, don't know Korean?

https://ebook-product.kyobobook.co.kr/dig/epd/ebook/E000013374986 here's one where the first volume's free for the next 5 days - no English storefront UI unfortunately, you might have to use a translator for the website

I know, I hate the app too - precisely why I was trying to get this book onto my ereader

Thank you I used google lens to navigate, but does it require phone permissions.

Comfirmed that it is protected by fasoo

DRMONE This Document is encrypted and protected by Fasoo DRM

i found this blog post from 2018, might potentially be helpful: https://archive.is/HLCPW

seems like it worked until ~2021 and got blocked, but perhaps there's a similar method still working..

https://last72.tistory.com/entry/교보문고-Ebook-DRM-removal

Do you have any good resources for learning how to decompile, edit, build, sign apks?

https://inv.nadeko.net/watch?v=AIqEA76_UkE

I use apklabs extension on visual studio code, I suggest using VSCodium. Additionally I use httptoolkit to check analyse internet connections.

Thanks!

Forgot to mention with split apks you need to merge the files, I use this app:
https://github.com/AbdurazaaqMohammed/AntiSplit-M

I looked at the code using jadx, it can decompiler apks easily. I found out that the licence is obtained from the server, you will have to do the rest of the work yourself.

Look for Public Class LicenceManager and drmkey, you should be able to find the dycrption algorithm.

The url for the license is ddrm.kyobobook.co.kr/drmone/mobile/gateway/license.do

https://github.com/skylot/jadx

This is my guess I believe each book has a different key and to get access you need the license. Since I didn't purchase the book I can't get access to the decryption key. I hope I am wrong because this is annoying drm.

I looked up the url in a search engine and found this it might help, I believe this is a guy to locate the decrypted files on a pc: https://bibliothecamysticadedantalian.tistory.com/m/45

Also an old study on how to break DRM on Kyobo:
https://seclab.skku.edu/wp-content/uploads/2018/04/NTMS_conference.pdf

If you ever manage to break it I will appreciate if you tell me how you did it. I believe extracting the decrypted book from a pc is the easiest method.