A few days ago the bad review jun received a private message from the audience, he heard that the color print will leave a tracking point on the paper, want to ask me if I really have this thing, the bad review jun is also the first time to hear, so a good study, these two days also did several experiments, today with everyone to talk about the safety of the printer.
What is Yellow Dot Tracking Technology
In 2017, the FBI arrested an employee of an NSA contractor accused of leaking confidential government documents.
The investigation revealed that she printed the documents on an NSA printer and mailed the scanned copies to a media outlet called The Intercept.
Originally, this kind of leak was not easy to find the ghost inside, but the NSA quickly locked her up. The key to exposing this inner ghost is a hidden function in the printer - "yellow dot tracking".
This is not some high-tech from the U.S. government, but a feature that can be found everywhere from your home to the office. But you may never know it.
In the early 1990s, HP, Xerox and other manufacturers have launched their own color printers, and color printing technology has slowly appeared on our desktops. But as the accuracy of color printing became higher and higher, the U.S. Treasury Department realized a problem - this thing can easily copy banknotes!
So in order not to turn the printer into a printing press, the U.S. government signed a secret agreement with hp, Xerox, Canon, Samsung and other mainstream printer manufacturers, requiring them to add the function of tracing the source of copies when the printer outputs files. And "yellow dot tracking" is one of the industry solutions.
This technique allows the printer to add a yellow dot pattern to the printout.
But these yellow dots are less than a millimeter in diameter and are almost invisible to the naked eye, but under a microscope or blue light, they are revealed.
They are arranged through special rules, and after deciphering, the printer model, serial number and specific printing time can be obtained.
However, this technology is not actually applied to banknotes, and the anti-printing technology that is really used on banknotes is "Omron Ring". If you take a closer look at the New Year's harvest, you can see that there are some small circles in the blank space, which are arranged in the form of the constellation of Orion, which is the "Omron Ring".
It is said that these circles can be recognized by printers, copiers, and even graphics software, and once the "Omron Ring" is found, the graphics software will stop working, and the printer will output a copy with severe color distortion.
Today, the world's major currencies such as the US dollar, the Renminbi, the euro, the Japanese yen, etc. are using this technology. However, for anti-counterfeiting reasons, the patent company did not publish the technical details, so we have no way of knowing how these devices recognize it.
Ah seems to be far away, let's go back to the "yellow dot tracking" technology.
Crack yellow dot tracking
This is the confidential document leaked by the NSA, which at first glance may seem nothing special, but if you enlarge the blank space of the document, you will faintly see a yellow dot. We can go inside the PS, work with the document with color inversion, and see a rectangular diagram of dots.
But at this point there are no points in the first row of the first column on the matrix, so we have to rotate the image 180 degrees to get the correct points.
We can then decode the image input on the Electronic Frontier Foundation's (EFF) website.
From this we get the result that this document is from the printer of model 54, serial number 29535218. Printed on May 9, 2017 at 6:20 a.m. In this way, the NSA can almost lock down who is using printer printing at that time, and it is easy to catch the inner ghost.
So far, though, EFF has only cracked Xerox's color printers (Xerox DocuColor), and we don't know how other brands of printers use yellow dots to track copy information.
Bad review experimental phase
In order to verify how common yellow dot tracking really is, I also did a small range of experiments. I picked a few print shops near the company and printed a few photos with different models of color laser printers to see if they were yellow dot tracking.
Capture the printer yellow dot
As it happens, the laser printers in these stores are not the same model. So these photos are from "Sharp mx6500", "Ricoh c5110", "Konica c1070", "Xerox Apeosport" and "Xerox C75", respectively.
It is true that there are no marks on it with the naked eye, but when I look at it with a microscope, I find yellow dots in the blank space, and there are such marks on all five pictures.
In this way, yellow dot tracking is indeed quite common.
Print the banknote
And I was also particularly curious about whether the Omron Ring was really anti-copy printing and PS processing, so I scavenged many of my colleagues' foreign currency experiments.
It was found that in addition to the US dollar, yen and euro, more than a dozen currencies, including the renminbi, could be printed and processed by PS.
Among them, the South Korean won and the renminbi both have Omron rings, so it is possible that Omron rings did not work. However, clicking on the information option in the PS prompt window will redirect you to the website of the Central Bank's Counterfeit Prevention and Control Group (CBCDG), which was established to prevent the use of personal computers, digital imaging equipment and software to make counterfeit banknotes, and the counterfeit Deterrence System (CDS) developed by it is different from the Omron Ring, and our machine obviously only has CDS anti-counterfeiting, and there is no Omron ring detection.
Oh yes, we also found a bug that on M1's native PS, even bills with CDS can be handled. It is recommended that Adobe fix it quickly.
Printer leaks
If you want to know which printers do not generate "yellow dot tracking", you can also find it on the website of the Electronic Frontier Foundation (EFF), which tested hundreds of printing devices of different models from different manufacturers and marked which ones had "yellow dot tracking".
Our country has also done a lot of research in this area, most of which are focused on criminal investigation work, such as this paper published in the journal of the Chinese People's Public Security University, which compares the tracking codes of Canon, Fuji, HP, Xerox and many other models of printers, and compares the morphological characteristics of their tracking points to identify color laser printed files.
Another paper, published in China Forensics, analyzed the lattice structure of printers tracking dark spots of various brands, and appraisers can identify the consistency of manufacturers and printers through copies. These studies are of great help to the relevant inspection work.
In fact, the printer has always been ignored by everyone security vulnerabilities, many people may feel that the printer belongs to the external device, and will not threaten our information security, but it also has the ability to process data independently, and itself also has to interact with the host.
And now many printers also have their own hard disk and other storage media, if you "hijack" such an unprotected printer, even if the host computer is powered off, you can print out the information in memory. I'm sure not many people have the habit of turning off the printer at will. So it's much easier to get a printer than you think.
In 2017, a 17-year-old gray hat from the United Kingdom was on Twitter because he blacked out more than 100,000 publicly accessed printers, and he issued instructions to these devices within 24 hours, and nearly 150,000 printers were printed on demand.
Of course, this little brother itself is not malicious, just want to remind everyone of the importance of printer security, it is likely to become an intrusion port for many network attacks, and the technical content is not as complicated as everyone thinks.
As early as the eve of the Gulf War, Iraq also planted a heel on the printer. They had purchased a batch of printer chips from France for air defense systems, and when the United States learned of this, it immediately sent spies to infiltrate Jordan, access these printing devices through certain channels, and replaced them with chips implanted with viruses.
Subsequently, these passive printers were transported into Iraq and connected to the Iraqi military's computers without any defense.
The U.S. military remotely activated the virus before the airstrike, and Iraq's air defense system was immediately paralyzed. Therefore, the old American warplanes can do whatever they want in Iraqi airspace with impunity.
Some even commented that it was a single printer that led to Iraq's rapid loss of the Gulf War.
In recent years, the mainland has also begun to pay attention to the safety of printers.
According to the announcement of the government procurement transaction, the printers purchased by the central government organs in batches are basically covered by brands such as HP, Kyocera, Xerox, Pentu, and Canon. Among them, "Bento" is the only domestic brand and the brand with the largest purchase volume.
This brand, which is not well-known in the consumer field, can win the largest order in government procurement, and the core reason is safety. Bentu is the earliest printer equipment manufacturer in the mainland to master the independent core technology, from the chip to the software completely independent development, it also eliminates the problem of leaking secrets from the source. (If You See Bento, remember to settle the advertising fee)
Imagine that if a company's confidential documents are stolen by printers, it is likely to cause commercial competition to fail, and if a country steals a large number of confidential documents, it will also cause major damage to national security interests.
end
Although the slogan of paperless society has been mentioned for a long time, we still have to print various documents every day, you may feel that you have no secrets to leak, but in today's general salary secrecy, even if there is a salary slip exposed, it can cause a lot of shock in the company.
So for individual users, you can't ignore the security risks of the printer, of course, you don't have to worry about the "yellow dot tracking" function, it is actually a kind of digital watermark, but the manufacturer has not fulfilled the obligation to inform the user.
What we should pay more attention to is actually to develop good printing habits, such as turning off the standby printing equipment, not exposing the printer to the public network, and so on. I hope this video can give you a wake-up call, do not ignore any of the devices connected to the host.
Well, this is today's content, I am a bad reviewer, if you like it, you are welcome to click three times, if you have anything you want to say, welcome to interact with us in the comment area and the bullet screen, and finally please please pay attention to us, we will see you next time ~
Choreographer: Yang Zi
Video Production: Bad Reviewer
Editor: Huan Yan (video) & Xuan Xuan (tweet)
bibliography
[1] NSA contractor Reality Leigh Winner faces prosecution for alleged leak of top-secret report ----ABC News
[2] Investigating Machine Identification Code Technology in Color Laser Printers -EFF
[3] List of Printers Which Do or Do Not Display Tracking Dots -EFF
[4] EURion constellation --WiKi
[5] How Yellow Printer Dots Outed Reality Leigh Winner As The One Leaking NSA Documents -Lawrence Systems
[6] A Preliminary Study on The Characteristics of Small Dots in Dark Codes in Color Laser Printed Files - Liang Lizheng, Huang Jiantong ( Chinese Min Public Security University)
[7] Study on the Dark Memory Characteristics of HP et al. Color Laser Printers - Wang Jie, Zhou Songdong, Li Jia, Zhang Weiguo (Chinese Forensic Appraisal)
[8] Rumor Shredder: Is Your Printer Safe? Read it - PConline
Stackoverflowin: A Story About the Internet of Things Impacting the Internet - CSDN
[9] Information security is autonomous and controllable, led by domestic printing Bento - Zhongguancun Online
[10] Centralized procurement project of printers in batches of central government organs in 2021 - Chinese government procurement network