In 2018, scientists at the TU Dresden analyzed the patterns of 106 printer models from 18 manufacturers and found four different encoding schemes. This code is not visible under normal conditions." Each copy shall be marked with a label which, if necessary, allows identification of the printing system with which it was created. Īs of 2011, Xerox was one of the few manufacturers to draw attention to the marked pages, stating in a product description, "The digital color printing system is equipped with an anti-counterfeit identification and banknote recognition system according to the requirements of numerous governments. Some printers arrange yellow dots in seemingly random point clouds.Īccording to the Chaos Computer Club in 2005, color printers leave the code in a matrix of 32 × 16 dots and thus can store 64 bytes of data (64×8). Thus, it can be analyzed even if only fragments or excerpts are available. For example, if the code consists of 8 × 16 dots in a square or hexagonal pattern, it spreads over a surface of about 4 square centimetres (0.62 sq in) and appears on a sheet of size A4 paper about 150 times. Their arrangement encodes the serial number of the device, date and time of the printing, and is repeated several times across the printing area in case of errors. The dots have a diameter of a tenth of a millimeter (0.004") and a spacing of about one millimeter (0.039"). The pattern consists of a dot-matrix spread of yellow dots, which can barely be seen with the naked eye. Yellow dots produced by an HP Color LaserJet CP1515n The Central Bank Counterfeit Deterrence Group (CBCDG) has denied that it developed the feature. In November 2004, PC World reported the machine identification code had been used for decades in some printers, allowing law enforcement to identify and track counterfeiters. 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 color laser printer. Patent No 5515451 describing the use of the yellow dots to identify the source of a copied or printed document. Xerox developed the machine identification code "to assuage fears that their color copiers could be used to counterfeit bills" and received U.S. In the mid-1980s Xerox pioneered an encoding mechanism for a unique number represented by tiny dots spread over the entire print area. In 2018, scientists developed privacy software to anonymize prints in order to support whistleblowers publishing their work. Developed by Xerox and Canon in the mid-1980s, its existence became public only in 2004. Yellow dots on white paper, produced by color laser printer (enlarged, dot diameter about 0.1 mm)Ī 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.
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