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

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

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 github.com/dfd-tud/deda ✊

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@douginamug

Check out your money for the EUrION constellation. In spite of the name, it's on US bills $5 and greater.

@joachim damn. And to think I had no idea I was producing these dots myself til last week!

@douginamug @joachim you produce much more than you think you do, that surveillance captitalism 101 :)

@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: en.wikipedia.org/wiki/EURion_c :P

@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.

@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?

@douginamug I know this case from EFF explanation several years ago. Thanks for sharing this important thing.

@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)

@c24h29clo4 Interesting! Will have to check that out. Housemate managed to identify them on a print, but not sure if he used color...

@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

@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)

@vfrmedia @c24h29clo4 @Siphonay we found them on prints from our Xerox Phaser 6510 (Germany)

@douginamug
Wow this stuff goes deeper
en.m.wikipedia.org/wiki/EURion
Now I wonder if my printer would let me copy a note - I won't try it though since it is internet connected...

@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.

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