A research team led by the Electronic Frontier Foundation (EFF) recently broke the code behind a number of tiny tracking dots that some color laser printers secretly hide in every document you print.
“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, Dell, Espon, etc. 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 would need a blue light, a magnifying glass, or a microscope.
The 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.”
“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. 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 Senior Staff Attorney Lee Tien.
Source: Net-Security
