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Beating the unique identifiers that printers can add to documents for security purposes is possible: you just need to add extra dots beyond those that security tools already add. The trick is knowing where to add them.
[...] researchers from the Technical University of Dresden [...] Timo Richter, Stephan Escher, Dagmar Schönfeld, and Thorsten Strufe reckon they've cracked the challenge of knowing how to anonymise printed documents, and presented their work to the Association of Computer Machinery's 6th ACM Workshop on Information Hiding and Multimedia Security in Innsbruck, Austria [the week of June 22].
In this paper, the TU Dresden researchers explain that they tested 1,286 documents printed on machines from 18 manufacturers, creating an extraction algorithm to identify well-known dot-patterns--and at the same time, discovering four previously undiscovered patterns coding at 48, 64, 69, and 98 bits.
Identifying new patterns is important, from a privacy point of view, since as the authors points out, an activist in a dictatorship could easily be unmasked by their printer (unless they happen to use a Brother, Samsung, or Tektronix printer, none of which seemed to carry tracking codes, the researchers said).
[...] The group has published [a] toolkit that automates the obfuscation workflow, here.
Previous: "Printer Dot Sanitisation" Software Seeks to Cleanse Yellow-Dot Watermarks
(Score: 5, Interesting) by DannyB on Thursday June 28 2018, @07:55PM (21 children)
My first thought about a DIY printer was something like the old dot matrix (gag) or the 1990s inkjet type printers. Using something like Makeblocks (that can build a 3D printer) it would Shirley be possible to make some sort of dot matrix or inkjet printer using off the shelf parts.
My next thought was a WinPrinter. Remember those? I don't. I only read about them on Slashdot. But they were like WinModems. (Really "Lose" printers and "Loose" modems.) The hardware was bare minimal. All control logic was in the software driver in Windows. Thus printing impacted your Window 95 box performance.
An old WinPrinter in granny's attic could probably be driven by an esp8266 or esp32 (think "arduino") type microcontroller.
You would at least know it only prints what you tell it to print.
Maybe a Hackaday project could be to take an off the shelf modern color printer and replace its guts with a modern cheap microcontroller. Maybe someone has already done such a thing and I'm not through enough to google it. Oh my.
To transfer files: right-click on file, pick Copy. Unplug mouse, plug mouse into other computer. Right-click, paste.
(Score: 4, Interesting) by deimtee on Thursday June 28 2018, @09:13PM (7 children)
If they decode the dot patterns, another interesting project might be to write a program to add user-defined dot codes to Brother, Samsung, or Tektronix printers. Print a different random SN into every document.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 4, Funny) by DECbot on Thursday June 28 2018, @09:49PM (1 child)
I assume you mean "random" as in "always the username and printer serial number of my smelly, annoying coworker that sits across from me."
cats~$ sudo chown -R us /home/base
(Score: 0) by Anonymous Coward on Sunday July 01 2018, @03:04PM
(Score: 1) by tftp on Friday June 29 2018, @01:34AM (3 children)
(Score: 0) by Anonymous Coward on Friday June 29 2018, @01:45AM (2 children)
I'd prefer HaHa'); DROP TABLE Printers;--
O just Bobby Tables [xkcd.com]
(Score: 2) by maxwell demon on Friday June 29 2018, @07:27AM (1 child)
Since it encodes serial numbers, I suspect the encoding doesn't cover the complete ASCII character set, but only numeric, or at most alphanumeric characters. So, no semicolon or quote for you to add.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by DannyB on Monday July 02 2018, @04:11PM
Does anybody still use ASCII? Try UTF-8!
Characters for line drawing. Playing cards. Musical and mathematical notation. All known human languages. Romulan, Klingon, Vorlon, Minbari, Narn, Cardassian, Centuari, Dwarvish and languages not yet invented. And best of all . . . emojis!
To transfer files: right-click on file, pick Copy. Unplug mouse, plug mouse into other computer. Right-click, paste.
(Score: 0) by Anonymous Coward on Friday June 29 2018, @01:39AM
Just be sure to that the dot pattern matches one of a printer with compatible toner properties to not give away the deception so easily.
(Score: 2) by takyon on Friday June 29 2018, @12:04AM
I'm sensing a new Kickstarter crowdfunding product.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by LoRdTAW on Friday June 29 2018, @12:36AM (11 children)
I've thought of this as an open project. The idea would be to make a simple black and white laser printer. Laser isn't that hard of a thing to build. You need a transfer drum and the laser is scanned across it using a rotating 4 sided mirror. The rotational speed of the mirror is synced with the feed speed of the paper rollers and you fire the laser to "draw" on the toner transfer drum. Then you heat the paper to fuse the toner and presto, you got a print. Harder than an ink jet mechanically, yea. An ink jet is much simpler with a easy feed system and simple print head setup. In a laser it seems that you have to keep the page moving so the scanner has to draw like a flying saw.
For software and communication I'd actually dump the current steaming shit pile of print protocols and simply setup the printer to accept a bitmap. If it were a plan 9 system I'd make it a 9p file server that serves up three files: bitmap, ctl, and status. A simple text string contains the page settings and the bitmap is what is printed on the paper. You first copy the bitmap and then the ctl string which triggers the printer to print. A third file can contain status information. Printing would look like this:
That's just off the top of my head. A script can automate that in a heartbeat. Another possibility is jobs can be spooled in the printer via a directory tree, each directory representing a job with its own ctl and one or more bitmap files depending on the number of pages. And the printer smarts should be minimal. It doesn't need to speak post script, it doesn't need fonts, it doesn't need any of that shit because the software generating the print should take care of that. A print is just a bitmap. no more, no less. I'd only concern myself with some quality settings such as some sort of dpi setting which also coincides with print speed, page scaling, paper size and if multiple trays were present. Just make it a simple bitmap to paper machine. And the same system can work just as easily with an inkjet which is a good starting point. Hmmmm...
(Score: 1) by tftp on Friday June 29 2018, @01:37AM
(Score: 2) by maxwell demon on Friday June 29 2018, @08:10AM (6 children)
Let's see.
Let's assume you want to print in 600dpi on A4 (the smallest of the usual paper sizes). An A4 paper has an area of 1/16 square meter, which is slightly less than 97 square inch. Let's assume 90% of that area can be printed on, that gives about 87 square inch, or at 600dpi, a bit more than 31 million pixels.
Let's assume just a B/W printout where each pixel can be either black or white, making one bit per pixel. Then you'll need roughly 31 megabits per page.
Let's take the lower end of typical laser printing speeds, 20 pages per minute, that is, 1/3 page per second. Then with your protocol you'll need to send about 10 megabits per second to the printer.
But what if we have a professional printer with 100 pages per minute, and want to print at 1200 dpi? That's already 100 megabytes per second. Hopefully your printer is connected with Gigabit ethernet …
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by maxwell demon on Friday June 29 2018, @08:11AM (3 children)
Err … should have been megabits, of course.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by maxwell demon on Friday June 29 2018, @08:21AM (2 children)
Err2 … and it would actually be 200 megabits per second (double the resolution is four times the pixels). Which actually drives home my point even more.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by opinionated_science on Friday June 29 2018, @12:05PM (1 child)
surely that's internal? That's why we have(had) Postscript. There's a computer in the printer to turn squiggle's into dots, so you are usually sending a lot less information.
I have heard rumours that in the olden days (1980's) , the printer cpu's were much faster than mainframes for calculation - if you write in Postscript that is ;-)
(Score: 2) by maxwell demon on Friday June 29 2018, @03:18PM
Read the post I replied to. In particular, note the following sentence from that post, emphasis by me:
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by LoRdTAW on Friday June 29 2018, @11:56AM (1 child)
Who says we're starting with 600dpi?
(Score: 2) by maxwell demon on Friday June 29 2018, @03:21PM
Well, for low resolution, I'd just reactivate my old nine-needle printer.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by tfried on Friday June 29 2018, @10:02AM (2 children)
Probably, a lot of very wonderful projects would never have been started, if their creators had not underestimated the required efforts by orders of magnitude. So, I'm not here to stop you. But just for reference: Have you ever seen one of those early photocopiers or laser printers? Try an image search for lbp-10 for instance (and that's not even the first laser printer, by far, only the first "desktop" model). The working principle has not really changed since then. Sure, the electronics will be a lot easier, today, and we have 3D-printing to help with the hardware. But I'll still be rather impressed, if you manage to craft as much as a reliable paper feed from the ground up.
Or, of course, you could use existing parts. But in that case, the easiest option would seem to be to buy a complete laser printer, and "simply" solder your own wires to the laser diode. You'll still have to solve the synchronisation, and possibly hack around self-tests, and such, but at least that sounds like something that could be solved with reasonable effort.
(Score: 0) by Anonymous Coward on Friday June 29 2018, @05:39PM
And ultimately you'll get the National Security Letter telling you you're getting a free update to your hardware NOW. Please leave the room NOW with these nice gentlemen.
(Score: 2) by DannyB on Monday July 02 2018, @04:12PM
Don't laser printers involve high voltages to charge the drum?
To transfer files: right-click on file, pick Copy. Unplug mouse, plug mouse into other computer. Right-click, paste.