A Machine Identification Code (MIC), also known as printer steganography, yellow dots, tracking dots or secret dots, is a digital watermark which certain color laser printers and copiers leave on every printed page, allowing identification of the device which was used to print a document and giving clues to the originator. Developed by Xerox and Canon in the mid-1980s, its existence became public only in 2004. In 2018, scientists developed privacy software to anonymize prints in order to support whistleblowers publishing their work.
History
In the mid-1980s Xerox pioneered an encoding mechanism for a unique number represented by tiny dots spread over the entire print area. Xerox developed the machine identification code "to assuage fears that their color copiers could be used to counterfeit bills" and received U.S. Patent No 5515451 describing the use of the yellow dots to identify the source of a copied or printed document.The public first became aware of MIC in October 2004, when it was used by Dutch authorities to track counterfeiters who had used a Canon...