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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: 1, Interesting) by Anonymous Coward on Thursday June 28 2018, @07:46PM (46 children)
An easier foolproof solution is to just pull out the yellow toner cartridge from the printer unless you need it.
(Score: 3, Informative) by frojack on Thursday June 28 2018, @08:14PM (12 children)
Too bad printers weren't designed by grown ups. They would have thought about that before making millions of printers.
Oh, wait. Take out toner cartridge - printer no-workie.
Substitute black toner cartridge for yellow toner cartridge, printer no-workie.
Substitute empty toner cartridge for yellow toner cartridge, printer no workie.
Break or disconnect the fuser heater for yellow, printer no workie.
...
I guess they must have has some internet Anonymous Coward's on the development team.
No, you are mistaken. I've always had this sig.
(Score: 0) by Anonymous Coward on Thursday June 28 2018, @08:32PM (5 children)
Most of the printers I checked just issue a toner empty/missing cartridge warning which you can skip, printer workie.
And in those which didn't you can trick it to sense an empty/missing toner cardtrige as full, printer workie.
Yes, I can guess some low end printer I didn't try won't work. Tough luck. Choose a printer from a more user friendly brand next time.
Too bad naysayer grown ups didn't even try before naysaying on the internet.
(Score: 2) by Freeman on Thursday June 28 2018, @09:07PM (1 child)
"more user friendly brand" We don't sell those kinds of printers in the USA. You can only get the $50 printers with the $100 ink replacements.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 0) by Anonymous Coward on Friday June 29 2018, @04:26AM
For a while there you could pick up a new printer for around AUS$30 with a full cartridge. It was cheaper just to buy a new printer on special than to buy new cartridges.
Now the cartridges come half or quarter filled.
(Score: 2) by frojack on Thursday June 28 2018, @09:10PM (2 children)
Toner empty/missing - No bypass. Printer no workie. (Lets face it: You didn't run ANY tests. I did on every laser I have at had both at home and in the office. 4 HPs, (color and b/w) Dells, new Brothers. None will print with one toner missing or one toner empty except an older Dell (Lexmark under the hood). It reverted to half-tone and printed everything in shades of grey, which probably had faint black dots.
I tested these because staff was moaning about not being able to print B/W when expensive color toner was gone.
Trick empty toner cartridge as full: Not as easy as it used to be (it never was actually easy).
Toner can be sensed electrically. You going to wire in a few millivolts into your cartridge contacts? I don't think so.
No, you are mistaken. I've always had this sig.
(Score: 0) by Anonymous Coward on Friday June 29 2018, @12:32AM
Do you know that only have to remove the toner cartridge and not the whole drum/cartridge assembly, right?
Some also may need to lock a microswitch or keep the toner chip in place.
(Score: 0) by Anonymous Coward on Friday June 29 2018, @04:28AM
Buy a HP Officejet?
They have decent Linux drivers with decent scanning software too.
(Score: 1, Interesting) by Anonymous Coward on Thursday June 28 2018, @08:39PM (5 children)
You can get third party refillable ink cartridges for many popular printers:
https://lightzonephoto.wordpress.com/2015/02/20/my-epson-r2400-conversion-to-third-party-inks/ [wordpress.com]
https://refreshcartridges.co.uk/ [refreshcartridges.co.uk]
I think it's possible to fill the yellow toner with something that readily evaporates.
(Score: 1, Informative) by Anonymous Coward on Thursday June 28 2018, @09:05PM (4 children)
The toner cartridge doesn't need to contain anything for the printer logic to detect it as full.
Do you realize that the "toner empty" flag doesn't actually check, weight or sense in any way the physical presence of toner at all?
These checks are just some sort of usage counter, smartchip, gears, or even embedded software all of which can be reset in a way or another without any real toner involved.
You always could buy a brand new toner cartridge, dump all the toner and clean the shell and then use it as it were full without actually printing anything ever with it.
(Score: 2) by frojack on Thursday June 28 2018, @09:12PM (3 children)
BS. Toner is electrically sensed, (it conducts electricity) not only in the cartridge but on the drum.
No, you are mistaken. I've always had this sig.
(Score: 0) by Anonymous Coward on Thursday June 28 2018, @11:33PM (2 children)
I don't know in what world you live in but in the real world toner is an insulator (it doesn't conduct electricity) to be able to hold any electrostatic charge and adhere to the photosensitive imaging drum.
That's virtually any existing laser printer technology based on electrostatic processes.
You can check it yourself printing a 100% fill area with the densest settings in any color you like, get a MOhm tester and verify that the resistence is out of range.
(Score: 2) by Deeo Kain on Friday June 29 2018, @11:22AM (1 child)
http://smallbusiness.chron.com/printer-low-toner-61441.html [chron.com]
(Score: 0) by Anonymous Coward on Friday June 29 2018, @04:23PM
Linked article author: Fred Decker
(Score: 2) by NewNic on Thursday June 28 2018, @08:24PM (26 children)
Since your "solution" doesn't actually work, I'll present two easier solutions:
1. Use a printer made by Brother, Samsung, or Tektronix.
2. Use a B&W printer.
lib·er·tar·i·an·ism ˌlibərˈterēənizəm/ noun: Magical thinking that useful idiots mistake for serious political theory
(Score: 3, Informative) by martyb on Thursday June 28 2018, @08:39PM (4 children)
I'll do you one better... I use a B&W Brother printer!
;)
Actually, I really do! It's a laser printer, prints quickly (20+ ppm), and I've never had a problem with it. Highly recommended.
Wit is intellect, dancing.
(Score: 0) by Anonymous Coward on Thursday June 28 2018, @08:59PM
Me too, though it was largely because I could get a laser printer for under $30.
That's less than the ink I'd have needed for the other printer.
(Score: 2) by frojack on Thursday June 28 2018, @09:29PM (2 children)
And you get light grey dots.
No, you are mistaken. I've always had this sig.
(Score: 1, Touché) by Anonymous Coward on Friday June 29 2018, @01:30AM (1 child)
link?
(Score: 0) by Anonymous Coward on Friday June 29 2018, @04:33AM
<sarcasm>Why don't you try</sarcasm>
"Pics or it didn't happen"
or
[citation needed]
or
{{Citation needed|reason=Your explanation sucked|date=June 2018}}
(Score: 3, Informative) by frojack on Thursday June 28 2018, @08:56PM (4 children)
B/W printers of modern manufacture do the same thing with black toner.
In very very tiny dots spread out so you won't notice them.
Also the EFF NOW says [eff.org]:
So unless your printer is vintage and has had ZERO firmware updates and ZERO driver updates you are probably going to get dotted.
No, you are mistaken. I've always had this sig.
(Score: 2) by NewNic on Thursday June 28 2018, @10:37PM (3 children)
Nothing is sure, but the EFF says:
"but, as far as we know, printers other than color laser and similar technologies do not deliberately encode their serial numbers in their output. "
Does the EFF consider a B&W laser to be included in the list of "similar technologies"? The rest of the page implies not.
lib·er·tar·i·an·ism ˌlibərˈterēənizəm/ noun: Magical thinking that useful idiots mistake for serious political theory
(Score: 2) by number11 on Friday June 29 2018, @02:35AM (2 children)
I don't care. I buy my printers at thrift stores or computer salvage places. They don't keep track of serial numbers. Just let somebody try to track a printer that was purchased by an organization 10 years ago and ultimately donated to a charity as a tax writeoff (they probably didn't keep records on who got what S/N, either). And besides, those 10 year old HPs are still damn good printers, they'll run until the rubber bits rot (and then you could find replacement parts, if you wished). Often only have a few thou pages on the clock, and toner is easy to find, and relatively cheap, because so many places use them.
Of course, if they actually grab my printer and do a test print, the ID is there. But for under $50, the far-sighted perp can buy one, use it for his nefarious deeds, and then donate it to a thrift store. And buy a different one.
(Score: 1, Informative) by Anonymous Coward on Friday June 29 2018, @09:49AM (1 child)
When you install the drivers they can silently report back to a server the serial number. Now there is a record of your IP+datestamp for that printer which can be used in the future to identify the various locations the printer has been previously seen. Perhaps it's a one-time ping, or maybe it attempts to register periodically (automatic driver updates). Then there is the OS itself to worry about. On Windows or Mac (and even some versions of Linux)? You better believe your hardware is being inventoried and reported, if for no other reason than to know which devices to continue supporting in the future. Keep in mind that yellow dot watermarking is the one we currently know about, I'm sure there are others; or soon will be.
I suppose running VPN at the router and getting your printers second-hand might work but I still wouldn't trust it. I use PIA (a good no-log provider) and there are times when the DNS gets screwed up and leaks, requiring a reconnect. Also, leave your phone at home when you go to buy that printer from the local pawn shop, pay with cash, and be sure to avoid all cameras along the way (good luck).
(Score: 0) by Anonymous Coward on Saturday July 07 2018, @04:59AM
They have Free Software drivers depending on which printer it is.
(Score: 3, Insightful) by martyb on Thursday June 28 2018, @09:24PM (12 children)
So, assuming for the sake of argument that we cannot block the introduction of watermarking dots -- be they yellow or B&W -- how effective would it be to print the same document on multiple printers?
What I mean is:
Alternatively:
One could even have a network of folk who print reams of blank pages and exchange these reams among themselves for re-re-reprinting!
All are off the top of my head, so I must be missing something?
Wit is intellect, dancing.
(Score: 3, Funny) by frojack on Thursday June 28 2018, @09:37PM (1 child)
I thought of the same thing.
But even in the your best case, they now have to track down three printers. If they all are owned by you, or a couple of your friends, it won't take long.
Print at the library, or coffee shop that keeps lousy records? Might work better.
Most librarians go out of their way to not keep records like that.
Still picking up your print while wearing surgical gloves and a Guy Fawkes mask is bound to attract attention.
No, you are mistaken. I've always had this sig.
(Score: 4, Insightful) by vux984 on Thursday June 28 2018, @10:43PM
"But even in the your best case, they now have to track down three printers. If they all are owned by you, or a couple of your friends, it won't take long"
No, in the best case, it would be useless.
Imagine, for example, that the printer printed a barcode on each page; if they printed a binary id as series of black and blank spaces.
( This is essentially what they are doing. )
So if you ran it through multiple printers, each printing different barcodes or binary strings over top of the previous, the resulting barcode would not scan at all, or the binary string would just have more and more of its 'bits' set to black. Figuring out which combinations of barcodes summed together are resulting in the the final result might be a very large range of possibilities. (ideally, with barcodes, after you ran it through enough printers, you'd have a solid black bar, or a solid black binary code (e.g. all 1s)... which would tell you very very little, since practically infinite combinations of printers would get you that "pattern" or result.
(Score: 4, Interesting) by NewNic on Thursday June 28 2018, @10:33PM
Your idea is probably only going to make it easier to identify you.
The patterns of marks won't be aligned, so there will now be 3 identifiable sets of marks, which will indicate 3 printers. Tracking down who has access to the set of 3 printers is likely to lead to a smaller set of people.
lib·er·tar·i·an·ism ˌlibərˈterēənizəm/ noun: Magical thinking that useful idiots mistake for serious political theory
(Score: 1, Informative) by Anonymous Coward on Thursday June 28 2018, @10:42PM (3 children)
Easiest option: buy printer second hand for cash and dispose of it after the printing.
(Score: 0) by Anonymous Coward on Friday June 29 2018, @04:38AM (2 children)
This is the best idea here. Not highly technical. Anyone can do it. It's not illegal. It's easy to find a second hand printer. It's not expensive.
Win!
(Score: 0) by Anonymous Coward on Friday June 29 2018, @05:33PM (1 child)
Except, as someone pointed out above, your printer driver is collecting serial numbers and chatting away merrily to Windows Update server.
Lose!
(Score: 0) by Anonymous Coward on Saturday July 07 2018, @05:02AM
Who says they use Windows? Or the proprietary drivers?
(Score: 3, Funny) by Snotnose on Friday June 29 2018, @12:17AM
Ahhh, CSB time. Around 1990, when copiers where the size of a washing machine/dryer set and came with service contracts, our printer got the name Bob Marley cuz it was always jammin. Tech came out and spent a full day tearing it down to bare metal, and the next day putting it all back together. He ran a ream of paper through it printing a test pattern, then went to a conference room to do his paperwork. I took that ream of test patterns out of the trash, put it into the paper bin, and ran a few copies. Took my copy superimposed over the test pattern to the tech, said "scuze me but" and showed him. He turned white. I held it together for maybe 2 seconds before busting up laughing.
When the dust settled America realized it was saved by a porn star.
(Score: 2) by maxwell demon on Friday June 29 2018, @04:24AM (3 children)
I've got a simpler idea: If your goal is not artistic, you might simply use a solid yellow background. That way there's no place where the yellow printer dots could be printed.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by deimtee on Friday June 29 2018, @06:49AM (2 children)
The logic is probably smart enough to XOR the dots. You will print a solid yellow with the same pattern of holes in it. And it doesn't just print once, it repeats all over the page. Even if you know what you're looking for, it's almost invisible to the naked eye. Once you know, it is easily viewed with a X10 magnifier.
The ones I have seen (Xerox digital publishing machines) it looks like a string of 4 x 4 grids of dots, only some of which print. I assume the grid makes it easy to identify, and the missing/present dots encode the info. (I think it was 4x4, it's been a while, might have been 5x5). Pretty sure it wasn't one character per grid though, the strings were way too short to encode a unique SN 1 to 1.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 2) by maxwell demon on Friday June 29 2018, @07:23AM (1 child)
In that case, make the background yellow random noise.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by deimtee on Friday June 29 2018, @09:12AM
The thing is, it is a very regular pattern of precisely sized dots that repeats multiple times. While you might obscure a random point on a grid, extracting a repeating signal buried in background noise is pretty much a solved problem.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 1) by koick on Friday June 29 2018, @12:06AM (2 children)
What about B&W photocopying your printout? It's a waste of paper, but yellow dots are gone.
(Score: 2) by maxwell demon on Friday June 29 2018, @04:26AM
If you do that, then why not use a B/W printer to begin with? It's cheaper, and cannot produce yellow dots anyway.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 0) by Anonymous Coward on Friday June 29 2018, @04:40AM
It probably puts the dots on photocopies too
(Score: 2) by nobu_the_bard on Thursday June 28 2018, @08:34PM (5 children)
Or print on yellow paper?
(Score: 2) by deimtee on Thursday June 28 2018, @09:01PM (3 children)
That won't work if they really want to find you. If they have the resources to analyse the dot pattern, identify the SN of the printer, and locate the owner of that printer, then they will be able to detect a difference between yellow paper and yellow paper with a dot of ink or toner on it.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 2) by Dr Spin on Friday June 29 2018, @07:24AM (2 children)
That won't work if they really want to find you.
Which brings us to the bit that puzzles me - assuming they have a metric shitload of yellow dots, how does that help them find me?
Besides which, if I wanted to print something anonymously, I would go to an Internet cafe in the mall and pay £1. Its not like their
CCTV cameras actually work.
The truely paranoid would buy a pen plotter from ebay, and spend 6 months trying to get the drivers to work.
Warning: Opening your mouth may invalidate your brain!
(Score: 3, Informative) by maxwell demon on Friday June 29 2018, @07:51AM (1 child)
The dots encode the serial number of the printer and the date/time of printing. If you bought the printer new through a big retailer, the serial number can probably be traced back to you. If you used your employer's printer, it can be traced back to your employer, who then probably can look up in the logs who sent print jobs to that printer at that time. For material that you wanted to keep anonymous, you probably chose a time where it was unlikely that others fetching printouts would see yours, therefore identification should be quite reliable.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 0) by Anonymous Coward on Saturday July 07 2018, @06:32AM
If I was doing something dodgy, I would buy a second hand printer from some dodgy looking guy in the street market.
Some people still take cash. Others live in third world countries where no one takes anything else. We don't all
live in Seattle.
I used to know a local company that claimed to do "Office clearances, with or without the owner's permission". (Last
I heard the owner was doing time, but I am sure he has strong competition).
(Score: 0) by Anonymous Coward on Friday June 29 2018, @04:35AM
Paper with an acidic layer to burn off the light dots but leave the heavy ink?