EFF Cracks Xerox Fingerprinting Code

17 Oct, 2005 at 7:55pm ET Article published in Tech

The Electronic Frontier Foundation has posted an article on how to pull the date, time, and printer serial number from forensic tracking codes in a Xerox DocuColor color laser printout.

The tracking codes are intended to be used to help law enforcement investigators solve crimes.

The DocuColor series prints a rectangular grid of 15 by 8 miniscule yellow dots on every color page. The same grid is printed repeatedly over the entire page, but the repetitions of the grid are offset slightly from one another so that each grid is separated from the others. The grid is printed parallel to the edges of the page, and the offset of the grid from the edges of the page seems to vary. These dots encode up to 14 7-bit bytes of tracking information, plus row and column parity for error correction. Typically, about four of these bytes were unused (depending on printer model), giving 10 bytes of useful data. Below, we explain how to extract serial number, date, and time from these dots. Following the explanation, we implement the decoding process in an interactive computer program.

Source: The Electronic Frontier Foundation

Comments

18 Oct 2005 ~ 3:03pm gtghm I'm sorry if I fail to see the point... but why would we even care about such a thing?

Just wondering?
"g"
18 Oct 2005 ~ 3:17pm FormFactor

gtghm wrote:

I'm sorry if I fail to see the point... but why would we even care about such a thing?

Just wondering?
"g"

Some people got bent out of shape because they felt the fact that the printers were secretly recording information was an invasion of their privacy.

The article sheds light on what exactly is being tracked, and how to find it.

Probably more useful for those in a tin foil hat.
18 Oct 2005 ~ 5:11pm airbornflght yeah, or if your in the counterfiting business, thats why they mainly started doing it. thats why i still use an injet printer, or the old laser printers.
18 Oct 2005 ~ 6:16pm RADA

FormFactor wrote:

Probably more useful for those in a tin foil hat.

DON"T TOUCH MY HAT!!!!! THE ALIEN-RUN FEDERAL LOCAL GOVERNMENT WILL BE ABLE TO READ MY THOUGHTS!
18 Oct 2005 ~ 6:39pm primesuspect Don't get too excited about inkjets - they do it too. It's been well known to anyone in the digital printing industry for years that this has been going on. Images on the web are similarly encoded. It's called steganography. Put it this way - almost any image you see is encoded in some way with meta information - be it serial number of device that it's been through, originating device, date, time, etc.
18 Oct 2005 ~ 6:57pm TheSmJ Yeah. So stop taking those kiddie-porn pics with your digital camera, k?
18 Oct 2005 ~ 7:31pm RWB

TheSmJ wrote:

Yeah. So stop taking those kiddie-porn pics with your digital camera, k?

Yeah you take them with a disposable film camera and send them in to be made. That should protect your ass from any trouble
18 Oct 2005 ~ 8:55pm Thrax Right until you have to give your name and phone number so they can call you when it's ready.
20 Oct 2005 ~ 6:45pm Mizugori viva polaroid

...just kidding! jesus
22 Oct 2005 ~ 4:50pm airbornflght I HAVE A SOLUTION!!!

heres what ya do. scan a $20 bill and make like 500 prints of it. (do the back side too ya idiot)

make sure ya print them on paper that mirrors the real stuff, then smash the printer into tiny bits and pieces.
23 Oct 2005 ~ 1:02am Mizugori actually you better burn those pieces into ashes then eat the ashes then crap outside and plant something in it... forensics these days, whew, you really gotta re-organize those atoms just to be safe

or you could um, get a job.
23 Oct 2005 ~ 11:46am primesuspect smbyte!
10 Nov 2005 ~ 8:06pm airbornflght he heh heh..i have a job, no wait. did./gonna