Many European eBook publishers and resellers are forgoing bulky encryption and instead going with watermarks. The vast majority of European readers do not like Adobe Digital Rights Management and other programs that make the transferring of their books overly complicated. Last month eBoekhuis, who is the leading company responsible for digital watermarks, made waves when it said it would provide Anti-Piracy company BREIN with user data. This obviously has caused an uproar, and many lawyers are looking into the legalities of this entire situation. In the meantime, what exactly is the technology being employed by eBoekhuis and BREIN?
A computer science student at the University of Twente managed to dissect the watermark encryption code to give us all a sense on how the underlying technology works. The digital book is served as an EPUB file which basically is an archive containing pages, stylesheets and images. Each page of the book has a transaction code that uniquely identifies a purchase at the vendor, the latter code represents the date and time of purchase as a big endian Unix 32-bit hex value.
The values are not viewable by the naked eye because it simply looks like a thin white line. If you use the eyedropper tool to inspect the image you will see that it consists of bars of variable widths in two different colors: white (#FFFFFF) and a little bit less white (#FEFEFE). When you replace either of the colors with black and enlarge the image vertically by 100 pixels you will see an image of a barcode. The entire image is just under 1 pixel in size, which makes it very small.