Printers betray document secrets

Ben Laurie ben at
Mon Oct 25 11:23:14 EDT 2004

Marshall Clow wrote:
> At 10:44 PM -0700 10/20/04, Bill Stewart wrote:
>> At 05:23 PM 10/18/2004, R.A. Hettinga wrote:
>>>  <>
>> It's not clear that they work at all with inkjet printers,
>> and changing ink cartridges is even more common than
>> changing laser printer cartridges.  If you're sloppy,
>> you've probably got a bunch of partly-used cartridges around,
>> so even if you want to print out a bunch of ransom notes
>> or whatever, you don't even have to go to Kinko's
>> to get them to be different.
> If you're really concerned about this, buy a cheap inkjet,
> use it for your purposes, then destroy it.

This only works if the marks are not such that the identity of the 
printer is linked to the marks (as opposed to being able to test whether 
a particular document was produced by a particular printer).

To be really safe, I'd suggest going somewhere without surveillance 
cameras, buying a printer for cash, using it and then destroying it.

Don't forget not to use your car and leave your mobile phone behind. Oh, 
and take the RFID tags out of your clothes.



ApacheCon! 13-17 November!

"There is no limit to what a man can do or how far he can go if he
doesn't mind who gets the credit." - Robert Woodruff

The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to majordomo at

More information about the cryptography mailing list