Ebook Formats, DRM and You — A Guide for the Perplexed

Post updated on 22nd March, 2013

DRM: What it is and why you should care about it.

DRM is used by publishers to restrict what you can do with your ebooks. DRM controls which devices you can use to read your ebook, and stops you converting your ebooks from one format to another.

DRM makes buying and using ebooks harder. When you first start using ebooks, you might not notice the restrictions very much. But the restrictions are there.

There are several different DRM schemes. Ebooks with one DRM scheme can’t be read on a device that uses a different DRM scheme. Some DRM schemes limit ebooks to one device only, so if you want to read that ebook on a different device, it’s necessary to download the ebook again. Others require new devices to be authorised by a central server on the Internet.

When you want to use a different ebook reader, or if the supplier stops supporting the ebooks you’ve bought, you may lose access to your DRMed ebooks. This has already happened to many people, with ebooks and other digital media.

So to be able to read your ebooks on all the devices you have now, and to be sure that you will still be able to read your ebooks in the future, you will want to remove the DRM.

Anti-Piracy Notice

Please only use this application for gaining full access to your own ebooks for archiving/converson/convenience. De-drmed ebooks should not be uploaded to open servers, torrents, or other methods of mass distribution. No help will be given to people doing such things. Authors, retailers and publishers all need to make a living, so that they can continue to produce books for us to read. Don’t be a parasite.

Current Ebook Formats and DRM schemes

There are three main current eBook formats.

  • ePub Defined by the IDPF and used by many ebook vendors.
  • PDF Created by Adobe, and in some forms an international standard. Less popular on ebook readers than on computer screen. PDF is hard to convert into other ebook formats.
  • Kindle Owned by Amazon, the Kindle ebook format is actually four different file formats.
    1. Mobipocket One of the oldest ebook formats, readily converted into other file formats.
    2. Topaz Created by Amazon, conversion to other formats relies on the quality of the OCR text in the format. The quality of conversions are therefore variable.
    3. Print Replica This is actually a PDF file wrapped in Amazon’s own packaging.
    4. KF8 Amazon’s newest ebook format, with rich formating capabilities similar to ePub, and readily converted to ePub.

There are several ebook DRM schemes

  • For ePub there are separate DRM schemes from Apple, Adobe and Barnes & Noble.
  • For PDF there are several different DRM schemes, several from Adobe, one from the Italian firm, ScuolaBook, and one from Barnes & Noble (NOOK Study).
  • For Kindle, DRM is provided by Amazon.
  • There are other schemes not covered by the tools in this blog.

Ways to Remove DRM

The tools in the archive maintained on this blog can remove all the kinds of DRM described above from ebooks, except for some of the older Adobe PDF DRM schemes, the ePub DRM scheme by Apple, and the NOOK Study PDF DRM scheme by Barnes & Noble. To remove DRM from ebooks sold by Apple, a separately maintained tool is required, described in my post Apple and ebooks: iBookstore DRM and how to remove it. There is currently no tools that removes DRM from Barnes & Noble NOOK Study ebooks. There are commercially available tools for the older Adobe PDF DRM schemes.

The simplest way for most people (especially Windows users) to remove the other kinds of DRM from their ebooks is to use the calibre plugin, as described in my post DeDRM plugin for Calibre: the simplest option for removing DRM from most ebooks.

Mac OS X 10.4 and later users who don’t want to use calibre can use the DeDRM AppleScript application, as described in my post, DeDRM AppleScript for Mac OS X 10.4 and later.

Windows users who don’t want to use calibre can use the DeDRM_App Python application, as described in my post, DeDRM Application for Windows XP and above.

Linux users should use the DeDRM plugin for calibre, or can extract the individual tools if they wish. Specific Linux instructions are included in the ReadMe that accompanies the DeDRM plugin.

A note about Amazon ebook formats

Amazon’s Kindle devices and software use a variety of ebook formats, and books bought from Amazon come in a variety of ebook formats. Amazon tries hard to hide this complexity from their customers, and does this by only sending each device ebook formats that it can understand.

Once the DRM is removed from an Amazon ebook, it becomes important to know the ebook’s format, so that it is not sent to devices that can not read its format.

For this reason, the tools will usually change the ebook file name extension. .mobi is used for Mobipocket format ebooks (all Kindle devices can read these). .azw3 is used for KF8 format ebooks. Not all Kindle devices can read these. Currently, Kindle 1, Kindle 2, Kindle 3 with firmware less than 3.4 and Kindle for iOS cannot read KF8 format ebooks, and ebooks in that format will need to be converted to Mobipocket format before transferring to such devices.

Amazon’s Topaz format cannot be read by any other devices, and is converted during decryption to a .htmlz archive that calibre can convert to other formats.

Obsolete Ebook Formats and DRM schemes

Fictionwise .pdb eReader format ebooks

The Fictionwise eReader format used its own DRM scheme. If you have the name and number key for your eReader ebooks, you can remove the DRM from them using any of the tools in the main archive.

Rocket .rb format ebooks

The Rocket ebook format used its own DRM scheme. If you are still able to read your Rocket ebooks on your Reader, you might be able to remove the DRM using the information and tools provided in the Other Tools folder of the main archive.

Microsoft .LIT format ebooks

The Microsoft LIT format used its own DRM scheme. If you are still able to read your Microsoft LIT ebooks on your computer, you can probably remove the DRM from them using the Convert LIT program, which is available at at http://www.convertlit.com/.

— Alf.