The idea that printer ink cartridges could be monitoring everyone’s printing activities may be too far a conspiracy theory. But in fact, although inkjet cartridges are not the tools of government secret agents, the reality is that the standard inkjet printer could have left a trail of hidden espionage all the way to the base.

It was a well-kept secret that only came to light relatively recently. Over twenty years ago, secret technology was created in an attempt to prevent counterfeit printing of paper money, official certificates, and classified documents. As a result, it became perfectly possible to trace the author of a forgery produced on high-quality advanced printing machines from the printed fake document.

All that is known of the detection method is that it was based on an encryption of microscopic dot patterns. Even now, the information is still classified. However, it is still possible to discover whether a printer still possesses the means to secretly encode a page of printed text by carefully examining the page under bright, strong light. A very close examination should begin to reveal a faint pattern of yellow dots covering the entire surface of the page.

The microscopic yellow dots are encoded, date and time stamped, allowing government or other official security agencies to trace back to the printer that originally created the page. Although ongoing official secrecy has always been maintained, some reports surrounding the ‘yellow dot code’ came to light in the periods of 2004 and 2008.

It is almost certain that the primary intention was just to have the ability to track serious large-scale counterfeiting operations using the limited number of high-tech printers available at the time. However, there have been big price cuts on mass-market color laser printers. It was probably not anticipated that, regardless of size or price, countless small and home-based businesses, as well as businesses and corporations, will have a printer containing tracking technology. Previous research found that top-brand color laser printers aimed at the home user market contained yellow dot encryption technology.

Unfortunately, there is nothing to prevent a single page printed on a ‘yellow dot code’ carried by a laser printer from being traced back to the original print source. However, considerable advances in tracking technology have been made in recent years. The upside is that a new generation of highly sophisticated and undetectable encrypted tracking sensors would almost certainly have replaced the original yellow dots.

It is therefore highly unlikely, though not entirely impossible, that any modern office or home business now owns a working inkjet printer containing the original yellow dot tracking technology.