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PRIVACY Forum Digest     Monday, 6 December 1999     Volume 08 : Issue 18


            Moderated by Lauren Weinstein (         
              Vortex Technology, Woodland Hills, CA, U.S.A.
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        IDs in Color Copies--A PRIVACY Forum Special Report
           (Lauren Weinstein; PRIVACY Forum Moderator)

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     Quote for the day:

        "It's not the heat, it's the humanity!"

           -- Jeff Douglas (Van Johnson)
              "Brigadoon" (MGM; 1954)


Date:    Mon, 6 Dec 99 13:31 PST
From: (Lauren Weinstein; PRIVACY Forum Moderator)
Subject: IDs in Color Copies--A PRIVACY Forum Special Report

Greetings.  We've recently seen a tirade of stories about "hidden"
identification codes and what many would consider to be surreptitious
centralized information flowing from various popular Internet products and
packages.  These have tended to highlight an important truth--whether or not
users really would be concerned about the particular identifiers or data
involved, they tend to get the most upset when they feel that an effort was
made to perform such functions "behind their backs."  While it can be argued
how routine, intrusive, or even mundane and innocent a particular case may
be, it's certainly true that people feel a lot better when they know what's
going on.

This issue isn't restricted only to the Internet world.  A case in point--
the recurring rumors floating around regarding the presence or absence of
identification codes in color copies (or color prints xerographically
generated from computer output systems).

A recent story involved a customer who was refused permission to make a
color copy of his driver's license (to deal with an identification problem
with his local telephone company).  A Kinko's (copying center) worker
reportedly told him that such a copy was "illegal," and could be traced back
to the store through a "hidden ID."

Regardless of whether or not the Kinko's employee was being overzealous in
his interpretation of the rules, what's really going on here regarding a
so-called hidden ID code?

In fact, rumors about this, often chalked up as an "urban legend," have been
circulating for a long time.  This is a bit ironic, given that in the
copier/printer industry it's been well known for years--no secret--that
"invisible" IDs are imprinted on virtually all color xerographic output,
from (apparently) all of the manufacturers.  But for persons outside of 
"the trade," this hasn't been as widely known (even though the issue goes
back to the early 90's, and the topic has appeared in publications such as
the Wall Street Journal).  However, it does not appear that the
privacy-related aspects of this technology have ever been subject to
significant public discussion.

In an effort to pin down the current state of the art in this area, I had a
long and pleasant chat with one of Xerox's anti-counterfeiting experts, who
is the technical product manager for several of their color-copying
products.  The conversation was quite illuminating.  Please note that the
details apply only to Xerox products, though we can safely assume similar
systems from competing manufacturers, although their specific policies may

Years ago, when the potential for counterfeiting of valuable documents on
color copiers/xerographic printers became apparent in Japan (where such
machines first appeared) manufacturers were concerned about negative
governmental reaction to such technology.  In an effort to stave off
legislative efforts to restrict such devices, various ID systems began being
implemented at that point.  At one stage for at least one U.S.
manufacturer, this was as crude as a serial number etched on the underside
of the imaging area glass!  

Modern systems, which are now reportedly implemented universally, use much
more sophisticated methods, encoding the ID effectively as "noise"
repeatedly throughout the image, making it impossible to circumvent the
system through copying or printing over a small portion of the image area,
or by cutting off portions of printed documents.  Effectively, I'd term this
as sort of the printing equivalent of "spread spectrum" in radio technology.

To read these IDs, the document in question is scanned and the "noise"
decoded via a secret and proprietary algorithm.  In the case of
Xerox-manufactured equipment, only Xerox has the means to do this, and they
require a court order to do so (except for some specific government
agencies, for whom they no longer require court authorizations).  I'm told
that the number of requests Xerox receives for this service is on the order
of a couple a week from within the U.S.

The ID is encoded in all color copies/prints from the Xerox color
copier/printer line.  It does not appear in black and white copies.  The
technology has continued to evolve, and it is possible that it might be
implemented within other printing technologies as well (e.g. inkjet).  At
one time there were efforts made to also include date/time stamps within the
encoded data, but these were dropped by Xerox (at least for now) due to
inconsistencies such as the printer clocks not being set properly by their
operators, rendering their value questionable.

It's interesting to note that these machines also include other
anti-counterfeiting measures, such as dumping extra cyan toner onto images
when the unit believes it has detected an attempt to specifically copy
currency.  These techniques have all apparently been fairly successful--the
Secret Service has reported something on the order of a 30% drop in color
copying counterfeiting attempts since word of such measures has been
circulating in the industry.  The average person might wonder who the blazes
would ever accept a xerographic copy of money in any case... but apparently
many persons are not very discerning.  I'm told that the Secret Service has
examples in their files of counterfeit currency successfully passed that was
printed on dot matrix printers.  So counterfeiting is certainly a genuine

OK, so now you know--the IDs are there.  The next question is, what does
this really mean?  Obviously the vast majority of uses for color copies are
completely innocuous or even directly beneficial to the public good (e.g.
whistleblowers attempting to expose a fraud against the public).  Is it
acceptable for an ID to be embedded in all color copies just to catch those
cases?  The answer seems to be, it depends.

In some cases, even having an ID number doesn't necessarily tell you who
currently owns the machine.  While some countries (e.g. China) do keep tight
reign on the ownership and transfer of such equipment, there is no
"registration" requirement for such devices in the U.S. (though the routine
servicing realities of large units might well create something of a de-facto
registration in many situations).

Xerox points out that non-color copies (at least on their machines) have no
IDs, and that most copying applications don't need color.  It is however also
true that as the prices of color copiers and printers continue to fall, it
seems only a matter of time before they become the "standard" even for home
copying, at which time the presence of IDs could cover a much vaster range
of documents and become increasingly significant from a routine privacy

It's also the case that we need to be watchful for the "spread" of this
technology, intended for one purpose, into other areas or broader
applications (what I call "technology creep").  We've seen this effect
repeatedly with other technologies over the years, from automated toll
collection to cell phone location tracking.  While there is currently no U.S.
legislative requirement that manufacturers of copier technology include IDs
on color copies, it is also the case that these manufacturers have the clear
impression that if they do not include such IDs, legislation to require them
would be immediately forthcoming.

It is important to be vigilant to avoid such perceived or real pressures
from causing possibly intrusive technology creep in this area.  In the
copier case, that ID technology being used for color copies could be
adapted to black and white copies and prints as well.  The addition of
cheap GPS units to copiers could provide not only valid date/time stamps,
but also the physical locations of the units, all of which could be
invisibly encoded within the printed images.  

Pressures to extend the surveillance of commercial copyright enforcement
take such concepts out of the realm of science-fiction, and into the range of
actual future possibilities.  What many would consider to be currently
acceptable anti-counterfeiting technology could be easily extended into the
realm of serious privacy invasions.  It would only require, 
as Dr. Strangelove once said, "The will to do so."

Perhaps the most important point is that unless we as a society actively
stay aware of these technologies, however laudable their initial
applications may often be, we will be unable to participate in the debate
that is crucial to determining their future evolution.  And it's in the
vacuum of technology evolving without meaningful input from society that the
most serious abuses, be they related to the Internet or that copy machine 
over on your desk, are the most likely to occur.

Lauren Weinstein
Moderator, PRIVACY Forum -
Co-Founder, PFIR: People For Internet Responsibility -
Member, ACM Committee on Computers and Public Policy


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