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I can has subtle spying?
Here’s an Instructable from the Electronic Frontier Foundation about tracking codes printers add to documents they print. Readers of Make learned about this back in volume 6; now, we’ve got a convenient video to send our friends:

Here’s the link to learn more on EFF’s site.

Luke Iseman

Luke Iseman

Luke Iseman makes stuff, some of which works. He invites you to drive a bike for a living (dirtnailpedicab.com), stop killing your garden (growerbot.com), and live in an off-grid shipping container (boxouse.com).


  • stunmonkey

    Alright, the lab coat is a little over the top, but the safety goggles are just egregious.
    Otherwise, great info.

  • Anonymously

    Would it be possible to load an image into Photoshop and overlay a yellow dot pattern to forge a code or mask one?

  • Thinkerer

    EFF could be much more effective by simply distributing overlay files to include with standard print routines to add random yellow dot codes.

    Simply printing a pure-white image (constructed in Photoshop or Paint) will give an easy reading of any codes being added by the printer, if any. No need to succumb to the shuck about buying a blue light.

    Finally, this type of steganography is easily obscured by a simple photocopying machine — eliminating the color information eliminates the dot codes, and color copies can be inspected for encoding but it usually doesn’t carry through.

    I’ll side with Stunmonkey above — I was waiting for a massive printer explosion or something with all the safety gear!