Recently you might have heard the news that a contractor for the NSA was arrested and charged with leaking classified information to the media, but it wasn’t so much that she was caught, but rather how she was caught. Apparently what helped the NSA narrow down their search was through the use of a printer.
It turns out that printers have actually been keeping tabs on what you print by embedding tracking codes in documents. In a report from Quartz, this revelation first came to light back in 2004 with an article published by PCWorld magazine in which it was revealed that your color printers have been hiding coded patterns in your printed materials that not only contain the printer’s serial number, but also the date and time that the documents were printed.
These dots are less than a millimeter in diameter and are printed in a shade of yellow that when printed onto a white background, are essentially naked to the human eye. It seems that this was a feature that was kind of a “don’t ask, don’t tell” kind of thing. Peter Crean, whose information the PCWorld article was based on, was a senior researcher at Xerox at that time, where he revealed that they only told customers about the feature if they had asked about it.
According to Crean, “We didn’t advertise it much to the people that had [the printers]. We didn’t not tell them if they asked. The salespeople were told, ‘Don’t lead with it in any sales, but if they ask you about it, you can tell them we have the security feature in there.’” This feature was apparently came about as governments were worried about how color printers could be used for forgery purposes, such as with money, and this was a solution known as printer steganography was came from Japan.
It also seems that this was not a standard feature and nor was it compulsory to be included, but printer manufacturers ultimately decided to go with it as some countries refused to allow printers to be imported without some kind of assurance that it would not be used for counterfeiting. That being said, the way the code is embedded varies from manufacturer to manufacturer, and apparently there is a new generation of codes that is said to be even harder to find than before.