

Analysis of Printer Watermarking Techniques - BrandonMarc
https://www.schneier.com/blog/archives/2014/10/analysis_of_pri.html

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genwin
I suspect this is why when you buy a printer at Fry's, you are asked your name
and phone number. That potentially matches you to the watermark even when you
pay cash.

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BrandonMarc
It sounds like the watermark includes encoded info about the network, IP
addresses, what have you. From one of Schneier's commenters, black-and-white
printers have their own method, involving tiny imperfections in certain
letters.

It reminds me of how Blizzard encoded info in World of Warcraft screenshots
(user, ip, campaign, timestamp, realm, what have you).

Scary stuff. Makes you want to not take it seriously, almost as a mental
defense mechanism.

~~~
DanBC
So I need to use anti-TEMPEST style techniques for my printer fonts now?

[http://www.cl.cam.ac.uk/~mgk25/emsec/softtempest-
faq.html](http://www.cl.cam.ac.uk/~mgk25/emsec/softtempest-faq.html)

