Still On the Subject of Laser Printers

In last Friday's newsletter, you recall, I talked about the danger we all face with out-of-control laser printers. Now let's look at the controversial side of these nefarious machines.

Fanning the flames of controversy, MIT Media Labs has launched a project called SeeingYellow.com to protest printer manufacturers whose laser printers secretly monitor use.

The project gets its name from some color laser printers that produce a nearly invisible grid of yellow dots on documents that store the serial number of the printer and the date stamp of the printed page -- something Benjamin Mako Hill and other members of MIT Media Labs' Computing Culture research group see as an incursion on our civil liberties. Among other things, the yellow-dot "watermark" lets the government and manufacturers track counterfeit currency generated on laser printers, as previously reported in Seeing Yellow Protests 'Big Brother' Laser Printers.

The Electronic Frontier Foundation has taken note posted a DocuColor Tracking Dot Decoding guide that explains how the Xerox DocuColor model printers produce the yellow dot pattern. It also provides a utility for translating your particular dot pattern to determine what information it stores. The DocuColor pattern is a repeating 15-x-8 grid of yellow dots on the entire page that encodes up to 14 7-bit bytes of data, such as model number, serial number, and date of printing. Other manufacturers such as Brother, HP, and so on also produce similar tracking patterns. (Question: Does my reporting on this qualify as "yellow journalism"?)

So while we're getting riled up about this, we should also take note that most digital camera have similar features. Serial numbers identifying the camera are embedded in images, thereby making it possible to identify the unique camera that took the photo.

Posted by Jon Erickson at 06:16 PM  Permalink