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Trivia [Today I Found Out] Printers print a series of dots on each page that people can’t see.

Eseru

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A Machine Identification Code (MIC), also known as printer steganography, yellow dots, tracking dots or secret dots, is a You do not have permission to view the full content of this post. Log in or register now. which certain color You do not have permission to view the full content of this post. Log in or register now. and You do not have permission to view the full content of this post. Log in or register now. leave on every single printed page, allowing identification of the device with which a document was printed and giving clues to the originator. Developed by You do not have permission to view the full content of this post. Log in or register now. and You do not have permission to view the full content of this post. Log in or register now. in the mid-1980s, its existence became public only in 2004.

It contains information about the printer. So if you print out a ransoms note at home they can more easily tie it to you.
This is how leaked intelligence was linked back to Reality Winner. She printed an NSA doc from work and handed it directly to whatever news source.
That news source uploaded that doc which had those unseen dots. They were able to trace it back to the printer from there.

The pattern consists of a dot-matrix spread of yellow dots, which can barely be seen with the ***** eye. The dots have a diameter of a tenth of a millimeter (0.004") and a spacing of about one millimeter (0.039"). 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. 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 You do not have permission to view the full content of this post. Log in or register now. about 150 times. Thus, it can be analyzed even if only fragments or excerpts are available. Some printers arrange yellow dots in seemingly random point clouds.

According to the You do not have permission to view the full content of this post. Log in or register now. in 2005, color printers leave the code in a matrix of 32 × 16 dots and thus can store 64 bytes of data (64×8).

As 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. Each copy shall be marked with a label which, if necessary, allows identification of the printing system with which it was created. This code is not visible under normal conditions."

In 2018, scientists at the You do not have permission to view the full content of this post. Log in or register now. analyzed the patterns of 106 printer models from 18 manufacturers and found four different encoding schemes.

Copies or printouts of documents with confidential personal information, for example health care information, account statements, tax declaration or balance sheets, can be traced to the owner of the printer and the creation date of the documents can be revealed. This traceability is unknown to many users and inaccessible, as manufacturers do not publicize the code that produces these patterns. It is unclear which data may be unintentionally passed on with a copy or printout. In particular, there are no mentions of the technique in the support materials of most affected printers (exceptions see below). In 2005 You do not have permission to view the full content of this post. Log in or register now. (EFF) sought a decoding method and made available a You do not have permission to view the full content of this post. Log in or register now. for analysis.

In 2018, scientists from the You do not have permission to view the full content of this post. Log in or register now. developed and published a tool to extract and analyze the steganographic codes of a given color printer and subsequently to anonymize prints from that printer. The anonymization works by printing additional yellow dots on top of the Machine Identification Code.
The scientists made the software available in order to support whistleblowers in their efforts to publicize grievances.


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[a curious question, and an answer from reddit]

How does the information about the printer connect it to the person doing the printing if the printer is owned by a company or many users are using it?

-- When done in a company, printer queuing is usually used at which point you just look at the logs who used the printer.
In a company I worked for, a digital copy of everything that was printed on company printers was also archived for up to a year.
But it mostly comes down to detective work.
What printer was it leads to Who had access leads to Who had motive.
Not knowing what printer printed it doesn't get you to the later two questions quickly.
Knowing can make all the difference.

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It's past 1AM and napadalaw nanaman ako kay reddit, and came upon a thread tungkol sa kung paano name-measure ng radio stations kung ilan yung mga listeners nila.
Pero yung mas naka kuha ng pansin ko is yung comment about printers and yung secret dots.
Mga trivias nga naman na malalaman mo sa Internet 😁
 

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