A German research group has developed a new kind of eBook DRM (digital rights management) that uses subtle changes to a text's grammar and punctuation to track unauthorised copying.
Think of it as the modern equivalent to copyright traps, the traditional tricks used by cartographers and authors to stop plagiarism. A trap street or trap dictonary entry is a deliberately fake entry, so if it turns up somewhere else it's a good cause to suspect unauthorised copying.
Researchers at the Darmstadt Technical University's Secure Documents by Individual Marking programme (or Sidim), with backing from the German government and publishing industry, have been exploring eBook DRM technologies like "text watermarks".
Every time someone buys a copy of a book, the publisher runs a programme that ever-so-slightly changes some of the text, be it its grammar, its punctuation or certain phrases. So, for example, the phrase "just outside the village he stopped at a nice restaurant" becomes "just outside the village, he stopped at a nice restaurant". Or the word "nice" might be replaced with "cute" or "little".
Instead of DRM that limits the number or type of devices that an eBook can be read on, the onus is on the consumer. They can do whatever they want with their eBook, but if their version of a novel turns up on a filesharing site then it's easy for the publisher to know exactly who uploaded it.
However, as Techcrunch points out, this might be hard to sell to authors -- there's no way of knowing in advance if one of the changes might alter some nuance of the text that they consider vital to the work.
The Sidim researchers have distributed a list of 15 example text watermarks to publishers in the mean time, asking them to assess which texts they think are the original, which are altered, and how obvious the alteration is. If it works, they won't be able to tell, but if it doesn't, it might need to be tweaked a little more.