EFF: Your Printer is Watching You

Researchers with the Electronic Frontier Foundation claimed Monday they have broken a code that some color laser printers print with every page. According to the group, the Secret Service has admitted they encoded the data into the pages in order to track counterfeiters, however the data stored in the code was not known before the discovery.

In one line of printers, the date and time the print was made, as well as the serial number of the printer were encoded into the document. The dots appear on printers by Xerox, Canon, HP and others, of which the group provided a list.

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


The dots are yellow in color and very small, and are repeated throughout a document. In order to see a pattern, the dots must be viewed under a magnifying glass or microscope, the EFF said.

To break the code, EFF researchers asked for submissions from supporters and then compared the patterns to one another to look for similarities and differences.

The EFF complains that while printer manufacturers have admitted they use the practice, there are no laws protecting U.S. citizens from abuse of the tactic.

"This technology makes it easier for governments to find dissenters," said EFF Senior Staff Attorney Lee Tien. "The logical next question is: what other deals have been or are being made to ensure that our technology rats on us?"

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