DeDRMing LCPA PDF files using Thorium reader

Someone asked me to remove DRM from a LCPA PDF file.

Using an old ereader, I hate DRM. So, I got to work !

I found this blog article which gave me direction on how to access the debugging interface of Thorium reader.

Be aware, Thorium 3.3.0 has closed the hole… But it works with 3.1.0. Here is a download link.

You need the LCP password to decrypt the book and access its content.

Start by unpacking the AppImage :

./Thorium-3.1.0.AppImage --appimage-extract

Now, launch Thorium :

./squashfs-root/thorium --remote-debugging-port=9223 --remote-allow-origins=*

Open your desired book in the app, then switch to your web browser. Go to http://127.0.0.1:9223/, select the $NAME_OF_BOOK - publication.pdf

Switch to the console, enter allow pasting to allow pasting (I know), then

this.PDFViewerApplication.download()

You should get a popup to download the file (or maybe it gets downloaded straigh in your prefered directory).

Either rename the file right away, and save, or save and rename it, as it is named publication.pdf.

Enjoy, and remember : Information wants to be free

As long as the code is running on your machine, you can do whatever the fuck you want, hence the move to cloud based apps.