Group cracks color printer tracking code

SAN FRANCISCO, Oct. 19 (UPI) -- A California consumer privacy group says it has cracked the once-secret code that allows law enforcement to track color printers by their printed pages.

The Electronic Frontier Foundation of San Francisco said it had cracked the code in a widely used line of Xerox printers. The code is an invisible set of dots that contain the serial number of the printer, as well as the date and time a document was printed.

With the Xerox printers, the information appears as a pattern of yellow dots, each only a millimeter wide and visible only with a magnifying glass and a blue light, the Washington Post reported.

The EFF said it has identified similar coding on pages printed from nearly every major printer manufacturer, including Hewlett-Packard Co.

The U.S. Secret Service acknowledged the markings, which are not visible to the human eye, are there, but it played down the use for invading privacy.

"It's strictly a countermeasure to prevent illegal activity specific to counterfeiting," U.S. Secret Service spokesman Eric Zahren said. "It's to protect our currency and to protect people's hard-earned money."