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New Technique Could Trace Documents By Printer
An anonymous reader submits "From this article at Purdue News, 'Researchers at Purdue University have developed a method that will enable authorities to trace documents to specific printers, a technique law-enforcement agencies could use to investigate counterfeiting, forgeries and homeland security matters.' The neat thing is that they are exploiting the characteristics of the print process itself to identify the printer." <update> One of the folks e-mailed me to say that the HP LaserJet 9000dn was one of the big ones tested with.
The problem here is many of the peices they would use to track the printers are integral parts of the replacable toner cartridges and printer ink kits. Only printers that have perm drums and heads will be easily traceable.
Xerox (and others, I'm sure) have done this for quite some time.
About 5 or 6 years ago a friend that owned a print shop and used a Xerox color laser printer told me about Xerox imprinting every print with a watermark that could be decoded to obtain the serial number of the actual machine used in the printing.
The watermark was undetectable to the human eye and didn't alter the presentation of the image.
They did this at the behest of the government because it's so easy to print money on these things. This way they can track the money back to the machine via the serial number.
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So basically, they are saying if they had the original printer, and the document they could put the two together.
In order for this to provide the means to track a forged document to it's source will require printers to be "tested" when sold so their "printing fingerprint" can be recorded.
Otherwise, at best if can serve as a confirmation, not a tracing method. This is how ballistic characteristics test are used. They are used to confirm that a gun fired a bullet, not to trace the bullet to the gun.
My Suburban burns less gasoline than your Prius.
Currency is printed by the fed, the biggest crook of all. And while the counterfeiters in Colombia and N. Korea do take a cut of the ill-gotten gains this way, and without permission at that, the crooks in charge trust them to not ruin it so completely that there is no wealth left to steal.
However, the fed can't have that same trust of joe sixpack, because he is an amateur crook, and might teach his buddies how to do the same. He is the biggest threat, and not to the economy... but rather to the scam itself.
If you bother writing your congressmen, add an extra sentence or two insisting that the government resume its right to coin money, and take it out of the hands of a private corporation owned by foreigners.
Things like this are troublesome, though:
One document obtained by the AP, a 1998 U.S. government business solicitation, mandated that "any color printer must include a tracing system that encodes system identification in any output. This will tie the output to the originating equipment so that forensic identification of the equipment is possible in the event of illegal printing of currency images due to failure or circumvention of the recognition system(s)...."
In a number of contracts where the US government has bought printers, they've required tracing features to be present-- effectively forcing them to be in printers sold to the general public as well. So effectively, many color printers are embedding their serial number in output documents. (And this is a lot more damaging-- saying this particular printer made a particular document, rather than a Epson Stylus 700).
He told us this story (BTW, I have no idea if it is true.) about how all photocopiers in the USSR had a serial number etched on the glass so the copies it made could be traced. Much easier to track down papers proclaiming the joys of Liberty I guess.
Well, that teacher has past on but I really wonder what he'd think of all this? All kidding aside is the US starting to look a little like the old USSR?
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