A new form of DRM developed in Germany alters words, punctuation and other text elements so that every consumer receives a unique version of an eBook. By examining these “text watermarks”, copies that end up on the Internet can be traced back to the people who bought and allegedly pirated them. The project is a collaboration between researchers, the book industry and the Government and aims to be a consumer-friendly form of DRM.
The ePub can be converted to PDF and then not be traced. Or even jpeg.