Secret Code in Color Printers Lets Government Track People
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. The U.S. Secret Service acknowledged yesterday that the markings, which are not visible to the human eye, are there.
Sleuths Crack Tracking Code Discovered in Color Printers, The Washington Post, October 19, 2005.
