It sounds like a conspiracy theory, but it isn't. The pages coming out of your color printer may contain hidden information that could be used to track you down if you ever cross the U.S. government.

Last year, an article in PC World magazine pointed out that printouts from many color laser printers contained yellow dots scattered across the page, viewable only with a special kind of flashlight. The article quoted a senior researcher at Xerox Corp. as saying the dots contain information useful to law-enforcement authorities, a secret digital "license tag" for tracking down criminals.

The content of the coded information was supposed to be a secret, available only to agencies looking for counterfeiters who use color printers.

Now, the secret is out.

Yesterday, the Electronic Frontier Foundation, a San Francisco consumer privacy group, said it had cracked the code used in a widely used line of Xerox printers, an invisible bar code of sorts that contains 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 EFF said it has identified similar coding on pages printed from nearly every major printer manufacturer, including Hewlett-Packard Co., though its team has so far cracked the codes for only one type of Xerox printer.

The U.S. Secret Service acknowledged yesterday that 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," agency spokesman Eric Zahren said. "It's to protect our currency and to protect people's hard-earned money."

It's unclear whether the yellow-dot codes have ever been used to make an arrest. And no one would say how long the codes have been in use. But Seth Schoen, the EFF technologist who led the organization's research, said he had seen the coding on documents produced by printers that were at least 10 years old.

"It seems like someone in the government has managed to have a lot of influence in printing technology," he said.

Xerox spokesman Bill McKee confirmed the existence of the hidden codes, but he said the company was simply assisting an agency that asked for help. McKee said the program was part of a cooperation with government agencies, competing manufacturers and a "consortium of banks," but would not provide further details. HP said in a statement that it is involved in anti-counterfeiting measures and supports the cooperation between the printer industry and those who are working to reduce counterfeiting.

Schoen said that the existence of the encoded information could be a threat to people who live in repressive governments or those who have a legitimate need for privacy. It reminds him, he said, of a program the Soviet Union once had in place to record sample typewriter printouts in hopes of tracking the origins of underground, self-published literature.

"It's disturbing that something on this scale, with so many privacy implications, happened with such a tiny amount of publicity," Schoen said.

And it's not as if the information is encrypted in a highly secure fashion, Schoen said. The EFF spent months collecting samples from printers around the world and then handed them off to an intern, who came back with the results in about a week.

"We were able to break this code very rapidly," Schoen said.
http://www.washingtonpost.com/wp-dyn/content/article/2005/10/18/AR2005101801663.html

Secret Code in Color Printers Lets Government Track You

Tiny Dots Show Where and When You Made Your Print

San Francisco - A research team led by the Electronic Frontier Foundation (EFF) recently broke the code behind tiny tracking dots that some color laser printers secretly hide in every document.

The U.S. Secret Service admitted that the tracking information is part of a deal struck with selected color laser printer manufacturers, ostensibly to identify counterfeiters. However, the nature of the private information encoded in each document was not previously known.

"We've found that the dots from at least one line of printers encode the date and time your document was printed, as well as the serial number of the printer," said EFF Staff Technologist Seth David Schoen.

You can see the dots on color prints from machines made by Xerox, Canon, and other manufacturers (for a list of the printers we investigated so far, see: http://www.eff.org/Privacy/printers/list.php). The dots are yellow, less than one millimeter in diameter, and are typically repeated over each page of a document. In order to see the pattern, you need a blue light, a magnifying glass, or a microscope (for instructions on how to see the dots, see: http://www.eff.org/Privacy/printers/docucolor/).

EFF and its partners began its project to break the printer code with the Xerox DocuColor line. Researchers Schoen, EFF intern Robert Lee, and volunteers Patrick Murphy and Joel Alwen compared dots from test pages sent in by EFF supporters, noting similarities and differences in their arrangement, and then found a simple way to read the pattern.

"So far, we've only broken the code for Xerox DocuColor printers," said Schoen. "But we believe that other models from other manufacturers include the same personally identifiable information in their tracking dots."

You can decode your own Xerox DocuColor prints using EFF's automated program at http://www.eff.org/Privacy/printers/docucolor/index.php#program.

Xerox previously admitted that it provided these tracking dots to the government, but indicated that only the Secret Service had the ability to read the code. The Secret Service maintains that it only uses the information for criminal counterfeit investigations. However, there are no laws to prevent the government from abusing this information.

"Underground democracy movements that produce political or religious pamphlets and flyers, like the Russian samizdat of the 1980s, will always need the anonymity of simple paper documents, but this technology makes it easier for governments to find dissenters," said EFF Senior Staff Attorney Lee Tien. "Even worse, it shows how the government and private industry make backroom deals to weaken our privacy by compromising everyday equipment like printers. The logical next question is: what other deals have been or are being made to ensure that our technology rats on us?"

EFF is still working on cracking the codes from other printers and we need the public's help. Find out how you can make your own test pages to be included in our research at http://www.eff.org/Privacy/printers/wp.php#testsheets.

Contact:

Seth Schoen
Staff Technologist
Electronic Frontier Foundation
seth@eff.org

Printer paranoia

Wednesday, October 19, 2005 - 02:26 PM

How creepy is this? Many colour laser printers spew out a matrix of tiny dots - invisible to the naked eye - which identify the serial number of the printer and the date and time the printing took place.