Machine Identification Code

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Hexagonal point marking on white paper, generated by a color laser printer (printout greatly enlarged, point diameter approx. 0.1 mm)

As Machine Identification Code (MIC) - even color printers mark , yellow dots (yellow dots), dots tracking (points to track) or secret dots (secret points) - a digital watermark denotes that certain color laser printers and - copiers on every printed page is attached.

The code can make it possible to identify the device with which a copy or printed piece was generated, and thereby provide information about the creator of the document.

technical realization

Marked yellow dots of an HP Color LaserJet CP1515n.

The marking consists of a dot matrix that is distributed over the entire print field. The dots are yellow, one tenth of a millimeter in diameter and about a millimeter apart. They can hardly be seen with the naked eye. Their arrangement contains the serial number of the device, the date and time of the printing process and data for error correction.

For example, if the code consists of 8 × 16 points in a square or hexagonal arrangement, it occupies an area of ​​around four square centimeters. It appears about 150 times on a DIN A4 sheet of paper. In this way, it can also be read out if only sections or fragments of the printed sheet are available.

Some printers also arrange yellow dots in seemingly random point clouds.

The Chaos Computer Club stated in 2005 that color copiers can mark in a matrix of 32 × 16 dots and can thus accommodate a data volume of 64 bytes.

To make visible

Yellow Dots: The code hidden on the printout in the form of tiny yellow dots using the example of an HP Color LaserJet 3700.

The Machine Identification Code can be made visible by printing or photocopying a color page and then scanning a small section of it with a high-resolution scanner. The yellow color channel can then be enhanced with a graphics program in order to make the points of the machine identification code, if available, clearly recognizable. With good lighting, however, a magnifying glass can be sufficient to see the tiny yellow dots. The yellow dots are clearly visible under UV light.

Machine Identification Code (MIC, yellow dots, tracking dots, secret dots) under UV light in regular (red and blue marked) and irregular arrangement (marked green).

With this steganographic process , high-quality printouts can also be identified as copies of an original document (e.g. a bank note ) under blue light . Shredded printouts can also be restored with these markings : the "Shredder Challenge" announced by the DARPA in 2011 was only completely solved and thus won by the "All Your Shreds Are Belong To US" team ( Otávio Good and two colleagues).

Protection of privacy

Copies or printouts of sensitive documents such as doctor's letters, bank statements, tax returns or company balance sheets can be traced back to the printer owner and the time of creation can be determined. Traceability is unknown to many users and is also not accessible. The code is not disclosed by the manufacturers. It is therefore initially unclear which data is unwillingly passed on with a printout or a copy. In particular, there is no information in the accompanying materials of most of the affected printers (see below for exceptions). The Electronic Frontier Foundation tried to decipher it and provided a Python script for analysis .

enlightenment

Xerox is one of the few manufacturers who point out the marking of the pages: the digital color printing system is equipped with a forgery-proof identification and banknote recognition system in accordance with the requirements of numerous governments. Each copy is provided with a label which, if necessary, enables the printing system with which it was made to be identified. This code is not visible under normal conditions.

Hewlett Packard Germany confirms that it has integrated MIC in all of its own printers. According to HP Germany, no firmware can be provided without a MIC. MIC is not mentioned in user manuals for HP printers. A return of a device is accepted by dealers with reference to the advice liability, if in the sales talk was not cleared up about MIC (which practically never happens).

Decoding

The Electronic Frontier Foundation's civil rights group called for hard copies to be sent in 2005 and subsequently decoded the pattern. The pattern has been demonstrated on a wide variety of printers from various manufacturers and models.

Decoding by the EFF.

Countermeasures

A research team from TU Dresden presented at a conference on 23/24. June 2018 in Innsbruck presented freely available software that "prints additional yellow dots on the paper, the hidden information becomes unusable."

Comparable procedures

Compared to the “yellow dots” that are visible under UV light or with a magnifying glass, other processes are not so obvious. For example, modulation of the laser intensity and a variation of gray levels in texts are not only conceivable, but have long been possible. It is not known whether manufacturers are already using these technologies.

Individual evidence

  1. ^ Frank Rosengart: data track paper . In: Chaos Computer Club (Ed.): Die Datenschleuder . The scientific journal for data travelers. No. 86 , 2005, ISSN  0930-1054 , p. 19–21 ( data track paper (PDF; 1.8 MB) [accessed June 27, 2018]).
  2. ↑ Contribution to Druckerchannel: Big Brother is watching you: Code decrypted with color lasers
  3. ↑ CONGRATULATIONS to "All Your Shreds Are Belong To US"! Defense Advanced Research Projects Agency, November 21, 2011, accessed June 12, 2014 .
  4. ^ Tip for Bad Guys: Burn, Don't Shred. Bloomberg Businessweek , December 15, 2011, accessed June 12, 2014 .
  5. ↑ Archived copy ( memento of the original from January 14, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. docucolor.cgi - CGI script to interpret Xerox DocuColor forensic dot pattern @1@ 2Template: Webachiv / IABot / w2.eff.org
  6. ↑ Xerox GmbH (Ed.): Xerox DocuColor® 6060 digital color printing system . Brochure. Neuss, Section “Technical Specifications of the Xerox DocuColor 6060 Digital Color Printing System”, p. 8 , col. 2 ( Xerox DocuColor® 6060 Digital Color Press (PDF; 1.4MB ) [accessed February 27, 2011]).
  7. ↑ Decoding information from the Electronics Frontier Foundation (English) ( Memento of the original from January 14, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / w2.eff.org
  8. ↑ Printer list that was checked for the code ( memento of the original from April 19, 2017 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / w2.eff.org
  9. ↑ Researchers lever out hidden data in printouts from orf.at, June 27, 2018, accessed June 27, 2018.
  10. ↑ Timo Richter, Stephan Escher, Dagmar Schönfeld, and Thorsten Strufe. 2018. Forensic Analysis and Anonymization of Printed Documents. In Proceedings of the 6th ACM Workshop on Information Hiding and Multimedia Security (IH & MMSec '18). ACM, New York, NY, USA, 127-138. doi : 10.1145 / 3206004.3206019
  11. ^ Poster from Purdue University Jan P. Allebach et al .: Identification, Authentication and Privacy

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