US: US computer printers contain secret software which enables the authorities to source all pages produced by them, the US Secret Service has confirmed. The service, which is responsible for tracking down counterfeiters, has acknowledged co-operation with computer printer manufacturers to install such software.
Last year, an article in PC World magazine revealed that printouts from many colour laser printers contained yellow dots scattered across the page, viewable only with a special flashlight.
The content of the coded information was supposed to be a secret, available only to agencies looking for counterfeiters who use colour printers.
But on Tuesday, the Electronic Frontier Foundation (EFF), a San Francisco consumer privacy group, said it had cracked the code used in a popular line of Xerox printers, an invisible bar code that contains the serial number of the printer as well as the date a document was printed.
The EFF said it has identified similar coding on pages printed from nearly every major printer manufacturer, including Hewlett-Packard.
The Secret Service on Wednesday played down fears that the coding represents an invasion of privacy. "It's strictly a countermeasure to prevent illegal activity specific to counterfeiting," agency spokesman Eric Zahren said.
It is unclear whether the yellow-dot codes have ever been used to make an arrest. And no one would say how long the codes have been in use. But Seth Schoen, the EFF technologist who led the organisation's research, said he had seen the coding on documents produced by printers that were at least 10 years old.
Xerox spokesman Bill McKee confirmed the existence of the hidden codes, but he said the company was simply assisting an agency that asked for help. HP said in a statement that it is involved in anti-counterfeiting measures.