A subtle background pattern generated by color laser printers helps authorities track counterfeit money or other documents back to the printer--and to the person who pressed the Print button.
Could you print counterfeit money, certificates, or other official documents on a color laser or LED printer? Some current printer models are indeed capable of creating reasonable facsimiles. The authorities, however, have already taken steps to thwart such activity.
Print any nontext image on your printer, and take a very close look at it under bright light: You might just be able to make out a subtle pattern of yellow dots covering the page. Those dots are a microscopic code that allows government agencies to trace the page back to the printer that created it--making the person who pressed the Print button pretty easy to find.
How is the code printed, and what data does it contain? That's secret, of course--printer vendors remain tight-lipped about the details. In 2005, the Electronic Frontier Foundation cracked the anticounterfeiting code on a Xerox color laser printer; the documents the EFF examined were date- and time-stamped, and could be traced to the location of the printer. Digging further in 2008, the EFF used the Freedom of Information Act to obtain hundreds of pages of documents on the use of printer-tracing technology from the U.S. Bureau of Engraving and Printing.
According to EFF staff technologist Seth Schoen, "the strategy of the government agencies that have worked on this technology--both U.S. and foreign governments--is mainly to keep as quiet as possible and hope that as little information as possible gets out." Read More
