Convert ACSM Files on Linux to ePub

When using Linux and buying ebooks, you will have to convert ACSM files on Linux to ePub. The Kobo store and other popular ebook stores don’t just give you a usable ePub, they often come in ACSM format. To actually read the book you’ve purchased you need to open that ACSM file up in Adobe Digital Editions and download an ePub. Then if you want to do anything with your book, like put it onto your own e-reader, you’re going to need to remove the DRM. The process is absurd but it’s the way things are right now.

What is an ACSM File?

First let’s answer, what is an ACSM file? ACSM stands for Adobe Content Server Message. This is a proprietary file format which acts as a “key” to the actual eBook hosted on Adobe Content Server. That’s right, the ACSM file you got from Kobo, Google Books, or somewhere else isn’t actually an eBook locked behind DRM, but essentially just a link to the book which you now need to download from Adobe.

How to Convert ACSM Files on Linux to EPUB

For this guide I am using PopOS, these commands should work on any other Ubuntu-based distro as well.

Install the Tooling

To do this, we are going to use WINE.

First, enable running 32-bit architectures if you have not already.

sudo dpkg --add-architecture i386

Install WINE from WineHQ. (If you hit any snags check the official install guide)

# Add the WineHQ repo and needed tooling
wget -qO- https://dl.winehq.org/wine-builds/winehq.key | sudo apt-key add -

sudo apt install software-properties-common

sudo apt-add-repository "deb https://dl.winehq.org/wine-builds/ubuntu/ $(lsb_release -cs) main"

Update your package list and install WineHQ

sudo apt update

sudo apt install --install-recommends winehq-stable winetricks winbind

Verify WINE is setup properly

wine --version

Convert ASCM to EPUB Using Adobe Digital Editions

Install dotnet40 as we need to for ADE, make sure to click through all the options

winetricks corefonts dotnet40

Download the Adobe Digital Editions installer for Windows

Next, use WINE to install ADE

wget https://adedownload.adobe.com/pub/adobe/digitaleditions/ADE_4.5_Installer.exe -P ~/Downloads

wine ~/Downloads/ADE_4.5_Installer.exe 

Again, click through all the options but avoid installing Norton, lol. Once the install is complete ADE should automatically open up.

Now go to help > authorize computer and sign in to Adobe, you will need to create an Adobe account if you don’t have one already.

wine ~/.wine/drive_c/Program\ Files\ \(x86\)/Adobe/Adobe\ Digital\ Editions\ 4.5/DigitalEditions.exe

Convert ACSM Files on Linux to EPUB

Inside Adobe Digital Editions, open the ACSM file. You can find your Linux file system inside the Z:/ drive.

The book you imported will now be available inside the wine file system in Documents/My Digital Editions/

ls ~/.wine/drive_c/users/$USER/Documents/My\ Digital\ Editions/

Install python + deps which will be needed to DeDRM the epub

winetricks python27 # this should also install pip
wine pip install pycryptodome

Download a 6.x.x release (https://github.com/apprenticeharper/DeDRM_tools/releases) of the DeDRM tool and extract DeDRM_Plugin/adobekey.py and DeDRM_Plugin/ineptepub.py.

Please note that 7.x.x versions will not work.

Now run adobekey.py in wine with Python

 wine ~/.wine/drive_c/Python27/python.exe adobekey.py 

Now use your locally installed python to deDRM the epub. Don’t forget to update those file paths.

python3 ineptepub.py adobekey_1.der ~/.wine/drive_c/users/chris/Documents/My\ Digital\ Editions/The\ Unicorn\ Project.epub ~/Downloads/test.epub

HUZZAH! It worked!

Now I can actually use the book that I paid for. You would be forgiven for thinking it would have been easier to just pirate the book since it likely would have been.

To convert more books just import them into ADE and then run the conversion command again

python3 ineptepub.py adobekey_1.der ~/.wine/drive_c/users/chris/Documents/My\ Digital\ Editions/another.epub ~/Downloads/another.epub

I love my Kobo e-reader. See it here on Amazon!

Sources

https://wiki.winehq.org/Ubuntu

https://github.com/BentonEdmondson/knock

https://superuser.com/questions/1027608/how-to-read-an-acsm-file-on-linux

https://askubuntu.com/questions/1301283/adobe-digital-edition-not-opening-in-wine