Doug Webb

Today I learned that many/most color laser printers layer an array of yellow microdots on top of documents 🔬

This Machine Identification Code https://en.wikipedia.org/wiki/Machine_Identification_Code encodes a print date and a serial number unique to the machine. It only became public knowledge in 2004, ~20 year after deployment 😑

The Technical University of Dresden released a tool 2 years ago to layer on _even more dots_ to render the MIC unreadable and aid whistleblowers publishing https://github.com/dfd-tud/deda ✊

Machine Identification Code - Wikipedia

Mar 2, 2020 at 8:31pmWeb
Show threadPort-humping pupperMar 4, 2020
@douginamug

Check out your money for the EUrION constellation. In spite of the name, it's on US bills $5 and greater.
Show threadJoachimMar 4, 2020
@douginamug That is how whistleblower Reality Winner was identified and arrested.
https://en.wikipedia.org/wiki/Reality_Winner#Intelligence_report_leak,_arrest,_potential_role_of_The_Intercept_in_her_arrest_and_sentencing
Reality Winner - Wikipedia

Show threadDoug WebbMar 4, 2020
@joachim damn. And to think I had no idea I was producing these dots myself til last week!
Show threadjumsMar 4, 2020
@douginamug @joachim you produce much more than you think you do, that surveillance captitalism 101 :)
Show threadkrugarMar 4, 2020
@jums @douginamug @joachim
There's a US FOIA answer with a list of manufacturers that include these, and it's ...basically all of them ;) since we're on this topic, if you want to add dots to your document for fun, use these: https://en.wikipedia.org/wiki/EURion_constellation :P
EURion constellation - Wikipedia

Show threadresist1984Mar 15, 2020
@krugar @joachim @douginamug @jums there's a lot of fuzziness there. For some printers there is a concrete "yes" to the #trackerdots question, and for others it's up in the air. Obviously ppl should avoid buying a printer that's confirmed compromised. Oki is a good bet. It's non-US, & Oki doesn't have scandals and dirt that most makers have.
Show threadresist1984Mar 15, 2020
@jums @douginamug @joachim @krugar This is where some of my info comes from: https://www.eff.org/pages/list-printers-which-do-or-do-not-display-tracking-dots
List of Printers Which Do or Do Not Display Tracking Dots

Warning (Added 2015) Some of the documents that we previously received through FOIA suggested that all major manufacturers of color laser printers entered a secret agreement with governments to ensure that the output of those printers is forensically traceable. Although we still don't know if this...

Electronic Frontier Foundation
Show threadresist1984Mar 15, 2020
@joachim @douginamug It's interesting that the dots were readable on The Intercept's *published version* of the documents, which seems to imply they did a really high quality color scan, no? Who does that? Why wouldn't a newspaper be smart enough to scan (presumably text) docs as a bitonal image where a yellow dot would be assigned white and not black?
Show threadAde Malsasa AkbarMar 4, 2020
@douginamug I know this case from EFF explanation several years ago. Thanks for sharing this important thing.
Show threadC24h29ClO4Mar 15, 2020

@douginamug so, this is really cool but it isn't universally applied to ALL prints from a colour laser.

What I've found is that colour laser printers at work won't print these for black and white docs - i suspect this is common since these dots are usually printed in yellow and you don't wanna spin up the colour laser elements if it isn't a colour print job. (it takes ~20 seconds longer to get ready to print colour than it does b+w)

Show threadDoug WebbMar 15, 2020
@c24h29clo4 Interesting! Will have to check that out. Housemate managed to identify them on a print, but not sure if he used color...
Show threadC24h29ClO4Mar 15, 2020
@douginamug keep in mind, these are corporate machines on a printers-as-a-service contract. No guarantee the feature isn't disabled to save toner or otherwise comply with business or legal privacy rules. I have definitely seen the dots around, just much less frequently on like, bulk letters and similar
Show threadAlex@rtnVFRmedia Suffolk UKApr 5, 2020

@c24h29clo4 @douginamug
@Siphonay

I've searched with UV torches and magnifiers for and /not/ found them on a variety of colour printers at work (also on similar contracts) - its possible this method is less often deployed on units outside the USA due to different privacy laws and there being other ways of preventing a printer being used for blatantly illegal purposes such as priinting a banknote,fake ID papers or event tickets (which used to be a thing in the 1990s)

Show threadDoug WebbApr 5, 2020
@vfrmedia @c24h29clo4 @Siphonay we found them on prints from our Xerox Phaser 6510 (Germany)
Show thread"Slide" BrombekMar 15, 2020
@douginamug
Anybody #FOSS firmware for my HP laser printer, please?
Show thread"Slide" BrombekMar 15, 2020
@douginamug
Wow this stuff goes deeper
https://en.m.wikipedia.org/wiki/EURion_constellation
Now I wonder if my printer would let me copy a note - I won't try it though since it is internet connected...
EURion constellation - Wikipedia

Show threadStewart RussellApr 5, 2020
@brombek @douginamug even knowing what hardware your printer has is a major challenge. Manufacturers change hardware mid-run, and drivers or internal compatibility layers make the correction.