Your Printer is Snitching On YOU!
Color laser printers have contained hidden surveillance technology since the mid-1980s. Xerox and Canon developed Machine Identification Code, a system of microscopic yellow dots that encode your printer's serial number and the exact date and time of every print job. This technology was implemented through a secret agreement between printer manufacturers and the United States Secret Service, revealed only through FOIA documents obtained by the Electronic Frontier Foundation.
The tracking dots are invisible under normal lighting conditions. Each dot measures one-tenth of a millimeter in diameter, arranged in a 15 by 8 grid pattern that repeats across every page. The encoded data includes the printer serial number in binary-coded decimal format, plus year, month, day, hour, and minute timestamps. Under UV light or blue LED illumination, the yellow dots become visible as black marks against white paper.
This surveillance system played a central role in the 2017 arrest of NSA contractor Reality Winner. When The Intercept sent leaked documents to the NSA for verification, analysts decoded the Machine Identification Code and traced the printout to a specific workstation. Winner received five years and three months in federal prison.
Researchers at TU Dresden analyzed 106 printer models from 18 manufacturers and confirmed four distinct encoding schemes across major brands including HP, Canon, and Brother. Their DEDA toolkit provides open-source anonymization capabilities for privacy-conscious users. Monochrome printers typically lack this tracking technology due to absence of yellow toner, though the EFF warns that other forensic methods may exist beyond visible yellow dots.
Sources
Wikipedia - Printer tracking dots: https://en.wikipedia.org/wiki/Printer_tracking_dots
U.S. Patent No. 5515451 - Xerox/Fuji Xerox image processing system: https://patents.google.com/patent/US5515451A/en
PC World - "Government Uses Color Laser Printer Technology to Track Documents" (November 22, 2004), Jason Tuohey
Electronic Frontier Foundation - List of Printers Which Do or Do Not Display Tracking Dots: https://www.eff.org/pages/list-printers-which-do-or-do-not-display-tracking-dots
EFF - Printer Tracking overview and FOIA findings: https://www.eff.org/issues/printers
EFF - DocuColor Tracking Dot Decoding Guide: https://w2.eff.org/Privacy/printers/docucolor/
TU Dresden - "Forensic Analysis and Anonymisation of Printed Documents" (ACM Information Hiding and Multimedia Security 2018): https://dfd.inf.tu-dresden.de/
Wikipedia - Reality Winner: https://en.wikipedia.org/wiki/Reality_Winner
Errata Security - "How The Intercept Outed Reality Winner": https://blog.erratasec.com/2017/06/how-intercept-outed-reality-winner.html
Quartz - "Computer printers have been quietly embedding tracking codes in documents for decades": https://qz.com/1002927/computer-printers-have-been-quietly-embedding-tracking-codes-in-documents-for-decades
DEDA toolkit GitHub repository: https://github.com/dfd-tud/deda
Regula Forensics - Printer Tracking Dots analysis: https://regulaforensics.com/blog/printer-tracking-dots/
Electronic Frontier Foundation - The Clipper Chip: https://www.eff.org/deeplinks/2015/04/clipper-chips-birthday-looking-back-22-years-key-escrow-failures
Electronic Frontier Foundation - CALEA (Communications Assistance for Law Enforcement Act): https://www.eff.org/issues/calea
Federal Reserve Bank of Minneapolis - Consumer Price Index (CPI) calculator showing dollar purchasing power decline: https://www.minneapolisfed.org/about-us/monetary-policy/inflation-calculator
Andrew Jackson's Bank War - veto message against Second Bank of the United States (1832)
Executive Order 11110 - Kennedy's order regarding silver certificates (June 4, 1963)
