Opening and converting ACSM files

In the world of electronic media, DRM technology is very important, because unlike analog information, digital content such as software, films, audio recordings, documents and books can, by nature, easily be reproduced and redistributed. This cripples the underlying business model, creating a situation, which is unsustainable for creators and copyright owners. For commercial digital publishers, the use of DRM systems to regulate access to protected intellectual property is therefore essential.

One such system, which is specifically designed to allow e-books and PDF content to be distributed and used securely across multiple devices, is Adobe Content Server (ACS). The company’s DRM server protects digitally published works using Adobe DRM copy protection. In this article, we explain the role that ACSMs – or ACSM files – play in this and how you can convert them.

An ACSM is a file that contains information about downloading a digital publication and is protected by the Adobe DRM copy protection. ACSM stands for Adobe Content Server Message, which tells us something about what these files – which are usually only a few kilobytes in size – really do; contrary to what many customers initially assume, an ACSM file is not the actual e-book, but a type of link or message between the user and the Adobe Content Server DRM software. This Adobe server application acts as an intermediary, which authorizes access to copy-protected digital documents (PDF, ePUB, ePUB 3).

If creators or copyright holders choose to use Adobe Content Server to protect e-books and other digital documents, when this content is purchased, it is automatically linked to the buyer’s Adobe ID. This ID is personal and non-transferable, and the user must set it up before purchasing any document with Adobe copy protection. Without this ID, the Adobe server application running in the background has no way of knowing whether to grant access to the copy-protected file.

The ACSM file is the first file the customer uses after making their purchase since it is the only file they can download at first. To open the ACSM file, as well as having an Adobe ID, the customer must also have installed the Adobe Digital Editions software on their system and linked it with their Adobe ID. Adobe Digital Editions then verifies the ID in order to check if the user is authorized to convert the ACSM file. If authorization is granted, the user can download their e-book in ePUB or PDF format. Adobe Digital Editions also uses the ACSM file to identify the download directory.

Creating your Adobe ID is the first necessary step towards opening an ACSM file, but you also need the appropriate software to convert the file (unless you wish to open the document with Adobe DRM protection on an e-reader which already has the necessary software).

Adobe’s in-house solution – Adobe Digital Editions – has been available to Windows and macOS users for years. More recently, Adobe has made the program available as a mobile app, meaning that ACSM files can also be opened on Android or iOS devices. You can download the installers from the Adobe download center (Windows and macOS) or from the App Store (iOS) or from Google Play (Android).

Having converted your ACSM file to PDF or ePUB format using Adobe Digital Editions, if you now want to transfer it to an e-reader, open the Adobe software again (or leave it open), and connect the e-reader to the computer via the USB port. The ADE software will automatically detect the device and prompt you to authorize it via the set-up wizard. Once it is authorized, the e-reader will appear in the list of bookshelves, and you can then drag and drop converted ePUB and PDF documents onto it.