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Altering Text In eBooks To Track Pirates
wwphx writes "According to Wired, 'German researchers have created a new DRM feature that changes the text and punctuation of an e-book ever so slightly. Called SiDiM, which Google translates to 'secure documents by individual marking,' the changes are unique to each e-book sold. These alterations serve as a digital watermark that can be used to track books that have had any other DRM layers stripped out of them before being shared online. The researchers are hoping the new DRM feature will curb digital piracy by simply making consumers paranoid that they'll be caught if they share an e-book illicitly.' I seem to recall reading about this in Tom Clancy's Patriot Games, when Jack Ryan used this technique to identify someone who was leaking secret documents. It would be so very difficult for someone to write a little program that, when stripping the DRM, randomized a couple of pieces of punctuation to break the hash that the vendor is storing along with the sales record of the individual book."
Shortly after the moveable type press got going in Europe, books of tables of interest rates were popular among the merchants. Of course, they all had to be laboriously hand calculated by mathematicians (long division was college undergraduate math in those days...). Publishers would sprinkle errors into the least signficant digits on various entries to use as evidence in copyright cases. Because, you know, if you had a printing press, you could make good money by pirating somebody else's table of interest rates.
And once you bought a book (with your own credit card), and then decide afterwards that you want to put it out there for pirates, suddenly, you realize that it's not such a good idea.
You realize it's not such a good idea... and 3/4 of a second later you just download it from another source. So you've really accomplished little.
Has Apple's similar approach impacted music piracy?
"Apple embeds your account information in all songs sold on the store, not just DRM-free songs. Previously it wasn't much of a big deal, since no one could imagine users sharing encrypted, DRMed content. But now that DRM-free music from Apple is on the loose, the hidden data is more significant since it could theoretically be used to trace shared tunes back to the original owner."
http://arstechnica.com/apple/2007/05/apple-hides-account-info-in-drm-free-music-too/