Cracking the Xerox tracking code

The Electronic Frontier Foundation said this week that it had cracked the code used in Xerox printers to embed details about the printer, including serial number, along with time and date information.

Laser printer manufacturers include the codes--which appear as small yellow dots visible under blue light--to help the Secret Service reduce counterfeiting.

The EFF reported the existence of the watermarks this summer, and this week published source code of a Xerox decoding program.

The blogging community was, predictably, appalled, although not that surprised. Speculation launched as to what other technology the government was tracking. And bloggers almost immediately began figuring out ways to get around the tracking.

Blog community response:

"But everyone should be worried about living in a world filled with innocuous-seeming devices that enable unprecedented, pervasive, routine surveillance."
--Copyfight

"I wonder if any similar deals have been struck with the feds related to inkjet printers -- the type found in most consumers' homes?"
--TechBlog

"Now that the code is known, it should be possible to forge the marks. For example, I could cook up an array of little yellow dots that encode any date, time, and serial number I like. Then I could add the dots to any image I like, and print out the image-plus-dots on a printer that doesn't make the marks. The resulting printout would have genuine-looking marks that contain whatever information I chose."
--Freedom to Tinker