Instructables

Yellow Dots of Mystery: Is Your Printer Spying on You?

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Imagine that every time you print a document, it automatically includes a secret code that could be used to identify the printer -- and, potentially, the person who used it. Sounds like something from a spy movie, right?

Unfortunately, the scenario isn't fictional. Most color laser printers and color copiers are designed to print invisible tracking codes across every single printed page of their output. These codes reveal which machine produced a document and, in some cases, when the document was printed or copied.

In this instructable, we'll describe three different ways to see the tracking dots your printer produces: with a blue light, with a microscope, or with a scanner. If you don't have the necessary equipment for a particular step, go on to the next one.

For further information, or to share your findings, please visit us at http://www.eff.org/issues/printers.

Want to help? Download test sheets at http://www.eff.org/wp/investigating-machine-identification-code-technology-color-laser-printers#help
 
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Step 1: Print a page with text/graphics

Picture of Print a page with text/graphics

Print out a page from a color laser printer. The page should use color and have some text or graphics on it. You can find a list of printers that we know print tracking dots at our website.

As you're looking for the dots, keep in mind that they're printed in a regularly repeating pattern across the entire page (not just in the corner of the page), and will be intermixed with other printed data.

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yieldlymph1 month ago

super

this is like the NSA spying on our phone conversations

paverphalange5 months ago

his is wrong in so many ways and quite disturbing as well come to think of it...

motherprune6 months ago

Thats sweet

cobbledbeard6 months ago

his is wrong in so many ways and quite disturbing as well come to think of it...

mousepaper6 months ago

Its fabulous :)

Its nice

amazedgreen6 months ago

Thats remarkable

fastbobble6 months ago

Thats astounding

gorgeddamp6 months ago


Thats astounding

clearedeager6 months ago

Its extraordinary

illrings6 months ago

Thats cold

airbugger7 months ago

Fascinating


Its extraordinary

headlymph7 months ago

good

tealrink7 months ago

GREAT

grousebandit7 months ago


Thats magnificent...

harechubby7 months ago

great

jiffymanager7 months ago

great

calmlunch8 months ago

good

spewlocks8 months ago

good

clapfilk8 months ago

super

good

spongeraffle8 months ago

Its nice

workexaminer8 months ago


Thats hip

bearblue9 months ago

nice

bearblue9 months ago

good

gazumpglue10 months ago

Very weird and strange.

Very weird and strange.
BunnyRoger1 year ago
Scary facts.
This is wrong in so many ways and quite disturbing as well come to think of it...
MAApleton1 year ago
I find this just a tiny bit silly, or it it just me?
jillef1 year ago
What about scanned documents? If a document if scanned from any scanner and then saved as a jpeg and sent as an email where the IP cannot be tracked is there any data that can be found then on those jpegs?
WOW!
Thank you so much :) You made my day !!
heckstallw1 year ago
Its usful
nice
siily
rickafost1 year ago
like
sensational and informative
thanks
itsme1235 years ago
why could not you just print a blank page many times thru different printers ( or print in white something like a period). running it thru top first , then bottom first then thru other printers, it would be hard to tell which printer made which mark making it hard to tell exactly where each mark came from
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