8 February 1998

    To: ukcrypto@maillist.ox.ac.uk
    Subject: It is really me - the story of Soft Tempest
    Date: Sun, 08 Feb 1998 15:09:40 +0000
    From: Ross Anderson <Ross.Anderson@cl.cam.ac.uk>

    Bruce Sterling, and others, have asked of the Washington Post story
    [see below]:

    > Is this story correct?

    The Washington Post gives a highly distorted account of some very
    important scientific work we have done. I suggest that list members
    read our paper - <www.cl.cam.ac.uk/~mgk25/ih98-tempest.pdf> - for
    themselves before getting carried away.

    The story is as follows. Bill G gave our department $20m for a new
    building, and his people said that what they really wanted from our
    group was a better way to control software copying.  So it would have
    been rather churlish of us not to at least look at their `problem'.

    Now the `final solution' being peddled by the smartcard industry (and
    others) is to make software copying physically impossible, by tying
    program execution to a unique tamper-resistant hardware token. We
    wouldn't like to see this happen, and we have already done a lot to
    undermine confidence in the claims of tamper-proofness made by
    smartcard salesmen.

    So Markus and I sat down and tried to figure out what we could do for
    the Evil Empire. We concluded that

    (1)  large companies generally pay for their software;

    (2)  if you try to coerce private individuals, the political backlash
         would be too much;

    so

    (3)  if the Evil Empire is to increase its revenue by cracking down on
         piracy, the people to go after are medium sized companies.

    So the design goal we set ourselves was a technology that would enable
    software vendors to catch the medium-sized offender - the dodgy
    freight company that runs 70 copies of Office 97 but only paid for one
    - while being ineffective against private individuals.

    We succeeded.

    In the process we have made some fundamental discoveries about
    Tempest. Army signals officers, defence contractors and spooks have
    been visibly flabberghasted to hear our ideas or see our demo.

    In the old days, Tempest was about expensive hardware - custom
    equipment to monitor the enemy's emissions and very tricky shielding
    to stop him doing the same to you. It was all classified and strictly
    off-limits to the open research community.

    We have ended that era. You can now use software to cause the
    eavesdropper in the van outside your house to see a completely
    different image from the one that you see on your screen. In its
    simplest form, our technique uses specially designed `Tempest fonts'
    to make the text on your screen invisible to the spooks. Our paper
    tells you how to design and code your own.

    There are many opportunities for camouflage, deception and misconduct.
    For example, you could write a Tempest virus to snarf your enemy's PGP
    private key and radiate it without his knowledge by manipulating the
    dither patterns in his screen saver. You could even pick up the signal
    on a $100 short wave radio. The implications for people trying to
    build secure computer systems are non-trivial.

    Anyway, we offered Bill G the prospect that instead of Word radiating
    the text you're working on to every spook on the block, it would only
    radiate a one-way function of its licence serial number.  This would
    let an observer tell whether two machines were simultaneously running
    the same copy of Word, but nothing more. Surely a win-win situation,
    for Bill and for privacy.

    But Microsoft turned down our offer. I won't breach confidences, but
    the high order bit is that their hearts are set on the kind of
    technology the smartcard people are promising - one that will
    definitively prevent all copying, even by private individuals. We
    don't plan to help them on that, and I expect that if they field
    anything that works, the net result will be to get Microsoft
    dismembered by the Department of Justice.

    Meantime we want our Soft Tempest technology to be incorporated in
    as many products as possible - and not just security products!

    So to Rainier Fahs, who asked:

    > If these rumors are true, I guess we will face a similar discussion on
    > free availability in the area of TEMPEST equipment. Does privacy
    > protection also include the free choice of protection mechanism?

    I say this: our discovery, that Tempest protection can be done in
    software as well as hardware, puts it beyond the reach of effective
    export control. So yes, you now have a choice. You didn't before,

    Ross Anderson

    ----------

    http://www.washingtonpost.com/wp-srv/WPlate/1998-02/07/060l-020798-idx.html

    British Technology Might Flush Out Software Pirates

    By John Burgess
    Washington Post Foreign Service
    Saturday, February 7, 1998; Page H01

    CAMBRIDGE, England— It's a technique that intelligence
    agencies have used for years: Park a van filled with
    monitoring gear near an embassy and listen for the faint radio
    signals that computers routinely emit when they are on.
    Analyze those signals for clues to the data that are on the
    computers.

    Now researchers at the University of Cambridge, home of
    groundbreaking work in intelligence over the years, are trying
    to adapt this technology to the fight against software piracy.
    With special code written into software, they say, computers
    could be made to broadcast beacons that would carry several
    hundred yards and identify the software they were running,
    complete with serial numbers of each copy.

    Vans run by anti-piracy groups could pull up outside a
    company's office and count the number of software signals
    emanating from it. If, say, 50 beacons for a particular title
    were detected but the company had licensed only two copies
    of the software, that could become evidence on which a court
    would issue a search warrant.

    Ross Anderson, a University of Cambridge lecturer who is
    overseeing the project, said the idea originated last year when
    Microsoft Corp. Chairman Bill Gates visited the university
    after his private foundation announced a $20 million donation
    to the school. Gates told officials that, among other things, he
    would love the university to come up with new anti-piracy
    techniques.

    So far, Microsoft isn't enthusiastic about the university's
    approach, Anderson said. "They have some reservations.
    Obviously there are Big Brother aspects," he said. A
    Microsoft spokeswoman said the company has no plans to
    adapt the technology.

    Emilia Knight, a vice president at BSA Europe, a trade group
    that combats software piracy, said such an anti-piracy system
    might be technically feasible. But she noted many practical
    questions on the legal side, such as how the system would
    differentiate between companies pirating software and those
    legally using multiple copies of programs.

    Knight said that concerns of privacy and consumer rights
    might make the system a no-go for industrialized countries.
    But in places like Eastern Europe, she suggested, where piracy
    is rampant and there is no tradition of such protections, the
    software signal detectors might be acceptable.

    Richard Sobel, a political scientist who teaches at Harvard
    University and researches privacy issues, called it "an
    appalling idea."

    "If the technology is there to identify what software people are
    using, there's the prospect to figure out what people are doing.
    . . . It sounds like a horrible violation of privacy," Sobel said.

    In Britain, however, it might seem less controversial. Here
    authorities have long used similar techniques to ferret out
    people who fail to pay the annual license fee of about $150
    that the law requires for each TV set in the country.

    Cruising the streets here are vans carrying equipment that can
    detect emissions from a TV set's "local oscillator," the part
    that turns a station's signal into a picture. If the gear senses a
    TV set inside a house from which there is no record of a
    license payment, this is used as evidence to levy fines.

    The system also can tell what channel people are watching
    because the oscillator gives off a slightly different signal for
    each one.

    Anderson's researchers have built a prototype that can detect
    the type of software running on a machine from short range --
    the hallway outside the room where the computer is running.
    Anderson said they are ready to build prototype hardware
    with a longer range, at a cost of about $15,000-$30,000 -- if
    the lab can find a customer. So far, none has stepped forward.

    © Copyright 1998 The Washington Post Company

    ----------

    Date: Sat, 7 Feb 1998 13:05:45 -0500
    From: Stewart Baker <sbaker@steptoe.com>
    To: ukcrypto <ukcrypto@maillist.ox.ac.uk>
    Subject: Ross, Is that really you?

         Today's Washington Post claims that a Cambridge research team led by one
         Ross Anderson is developing technology that would require all personal
         computers to broadcast the identity of all programs they are running so
         that anti-piracy investigators can sit outside universities and businesses
         and check to see whether the folks inside are running more programs than
         their licenses allow.

         The article says that even Microsoft thinks this might go too far in
         invading the privacy of computer users. But advocates for the technology
         claim that it will work fine in benighted Eastern European countries where
         piracy is rampant and the natives are used to having their privacy invaded.

         This raises at least three questions:

         1.  Is this story correct?

         2.  If so, is the Ross Anderson it describes the same Ross Anderson known
         on this list for his attacks on Big Brother?

         3.  If so, are we to understand that Ross objects not so much to invading
         privacy as to government competition in that endeavor?

         Stewart Baker

    For TEMPEST information see: http://www.eskimo.com/~joelm/tempest.html