The Risks Digest

The RISKS Digest

Forum on Risks to the Public in Computers and Related Systems

ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator

Volume 18 Issue 56

Thursday 31 October 1996

Contents

o The next stage of Differential Fault Analysis
Adi Shamir
o AOL Bans All Mail from 53 "Junk Mail" Domains
Edupage
o "Fall back, free parking; spring forward, pay more"
Bear Giles
o Cruise Missile software bugs
Kofi Crentsil
o Tote Board Crash at Breeder's Cup
Tony Harminc
o ATM problems in Canada
Richard Akerman
o Re: Beating the GRE: What time zone are you in?
Li Gong
Bear Giles
o More Personal Information Databases
Lauren Weinstein
o Where Wizards Stay up Late: Book Review
Tom Perrine
o Info on RISKS (comp.risks)

The next stage of on Differential Fault Analysis

Adi Shamir <shamir@wisdom.weizmann.ac.il>
Thu, 31 Oct 1996 21:27:44 -0800
  The Next Stage of Differential Fault Analysis:
  How to break completely unknown cryptosystems, 30 October 1996 (draft)

  Eli Biham, Computer Science Dept., The Technion, Israel
  Adi Shamir, Applied Math Dept., The Weizmann Institute, Israel

The idea of using computational faults to break cryptosystems was first
applied by Boneh Demillo and Lipton to public key cryptosystems, and then
extended by Biham and Shamir to most types of secret key cryptosystems.
[See RISKS-18.54.]  In this new research announcement, we introduce a
modified fault model that makes it possible to find the secret key stored in
a tamperproof cryptographic device even when nothing is known about the
structure and operation of the cryptosystem. A prime example of such a
scenario is the Skipjack cryptosystem, which was developed by the NSA, has
unknown design, and is embedded as a tamperproof chip inside the
commercially available Fortezza PC cards. We have not tested this attack on
Skipjack, but we believe that it is a realistic threat against some
smart-card applications that were not specifically designed to counter it.

The main assumption behind the new fault model is that the cryptographic key
is stored in an asymmetric type of memory, in which induced faults are much
more likely to change a 1 bit into a 0 than to change a 0 bit into a 1 (or
the other way around). CMOS registers seem to be quite symmetric, but most
types of nonvolatile memory exhibit some degree of asymmetry. For example, a
1 bit in an EEPROM cell is stored as a small charge on an electrically
isolated gate. If the fault is induced by external radiation (e.g.,
ultraviolet light), then the charges are more likely to leak out of the gate
than to be forced into the gate.

To make the analysis simpler, we assume that we can apply a low-level
physical stress to the tamperproof device when it is disconnected from
power, whose only possible effect is to occasionally flip one of the 1 bits
in the key register to a 0. The plausibility of this assumption depends on
numerous physical and technical considerations, which are beyond the scope
of this note.

We further assume that we are allowed to apply two types of cryptographic
functions to the given tamperproof device: We can supply a cleartext m and
use the current key k stored in the nonvolatile memory of the device to get
a ciphertext c, or we can supply a new n-bit key k' that replaces k in the
nonvolatile memory.

The cryptanalytic attack has two stages:

1. In the first stage of the attack, we keep the original unknown secret key
k stored in the tamperproof device, and use it to repeatedly encrypt a fixed
cleartext m_0. After each encryption, we disconnect the device from power
and apply a gentle physical stress. The resultant stream of ciphertexts is
likely to consist of several copies of c_0, followed by several copies of a
different c_1, followed by several copies of yet another c_2, until the
sequence stabilizes on c_f. Since each change is likely to be the result of
one more key bit flipping from 1 to 0 (thus changing the current key k_i
into a new variant k_i+1), and since there are about n/2 1 bits in the
original unknown key k, we expect f to be about n/2,and c_f to be the result
of encrypting m_0 under the all-zero key k_f.

2. In the second stage of the attack, we work our way backwards from the
known all-zero key k_f to the unknown original key k_0. Assuming that we
already know some intermediate key k_i+1, we assume that k_i differs from
k_i+1 in a single bit position. If we knew the cryptographic algorithm
involved, we could easily try all the possible single bit changes in a
simple software simulation on a personal computer, and find the (almost
certainly unique) change that would give rise to the observed ciphertext
c_i. However, we don't need either a simulator or knowledge of the
cryptographic algorithm, since we are given the real thing in the form of a
tamperproof device into which we can load any key we wish, to test out
whether it produces the desired ciphertext c_i. We can thus proceed
deterministically from the known k_f to the desired k_0 in O(n) stages,
trying O(n) keys at each stage. The attack is guaranteed to succeed if the
fault model is satisfied, and its total complexity is at most O(n^2)
encryptions.

This seems to be the first cryptanalytic attack that makes it possible to
find the secret key of a completely unknown cryptosystem in polynomial time
(quadratic time in our case). It relies on a particular fault model that
seems to be realistic, but requires further study.  In the full version of
this paper, we'll discuss numerous extensions of the attack -- including the
analysis of more complicated fault models in which the sequence of corrupted
keys forms a biased random walk in the space of 2^n possible keys.


AOL Bans All Mail from 53 "Junk Mail" Domains (Edupage, 29 Oct 1996)

Edupage Editors <educom@elanor.oit.unc.edu>
Tue, 29 Oct 1996 21:17:27 -0500 (EST)
America Online's new "Preferred Mail" junk e-mail blocking tool was
activated several days ago on all 6.5 million accounts;  it blocks all
e-mail from a list of (currently) 53 network domains that AOL has identified
as junk e-mailers.  Many of the domains have been used in the past by
Stanford Wallace, who is suing AOL for blocking his messages. One blocked
domain, managed by an Internet service provider called Cybercom, has been
tentatively removed from AOL's prohibited list, after protesting that it had
been placed on the list not because of its own actions but because two of
its 1500 clients sent adult-oriented junk e-mail, causing AOL immediately to
block all mail to AOL subscribers from any Cybercom customer.  (*Atlanta
Journal-Constitution*, 29 Oct 1996, D4)

  [Following up on this strategy, the next step
  would be for AOL to block all mail from AOL!  PGN]


"Fall back, free parking; spring forward, pay more"

Bear Giles <bear@tigger.cs.colorado.edu>
Wed, 30 Oct 1996 18:27:57 -0700 (MST)
The University of Colorado at Boulder has replaced the mechanical parking
meters in severals lot with a centralized computerized version that prints
a receipt convenient when challenging parking tickes. (Or is that
"convenient for them," since you need this receipt to successfully challenge
parking tickets?  :-) The two spots I use are in prominent locations -- one
is across from Regents Hall, the other is adjacent to the Police building.
I mention this because one would expect parking lot monitors to frequent
these sites...

Yet is it any wonder that I was a scofflaw during my classes on Monday
afternoon (on the first school day after the return to Mountain Standard
Time), since this high-tech solution to a simple problem made it impossible
to pay for my first hour of parking?

The flip side is worse -- if ticketed I could make a legal defense that
"what isn't permitted can't be compelled."  Unlucky visitors in the spring
can't make such a claim and may be forced to pay for an additional hour of
parking.

Bear Giles  bear@indra.com


Cruise Missile software bugs

<crentsil.k@atomcon.gc.ca>
Thu, 31 Oct 1996 07:41:46 -0500
I don't remember seeing anything in RISKS on software bugs deflating the
success rates of recent cruise missile strikes on Iraq.  It all sounds very
similar to the Ariane-5 software reuse fiasco.  Below are the relevant
excerpts from David A. Fulghum's "Hard Lessons in Iraq Lead to New Attack
Plan" in the September 16 1996 issue of *Aviation Week & Space Technology*
(pp. 24-25).

The article states: "Bomb damage assessment of the initial cruise missile
strike indicates that three of the 10 targets attacked by 13 Air Force
CALCMs (Conventional Air-Launched Cruise Missiles) emerged with "no
detectable damage," according to a U.S. intelligence report.  The Boeing
built CALCMs, converted from Cold War-era nuclear weapons at a cost of
$165,000 each, were launched from two B-52H bombers over the Persian Gulf."

Apparently: "Part of the problem with the CALCMs were that they were fired
at targets they were not designed to destroy, a product of hasty planning,
according to a senior Pentagon official. Air Force success rates were
further deflated because of missile computer programming quirks."

Further on: "Another CALCM target escaped damage because of a software
targetting quirk left over from its nuclear role. If two CALCMs are aimed at
the same target at the same time, one of the missiles will re-aim itself at
the next highest priority target. In the initial raid, one CALCM missed the
target while the other went on to the next site."

The risks of reusing software without proper testing for the new application
are obvious.

Kofi Crentsil (crentsil.k@atomcon.gc.ca)


Tote Board Crash at Breeder's Cup

"Harminc, Tony" <tzha0@toraag.com>
Wed, 30 Oct 96 15:34:00 PST
The Breeder's Cup - an American horserace being run for the first time in
Toronto last Saturday - suffered from various organizational difficulties,
according to an article in the Toronto _Globe & Mail_ on Monday Oct. 28,
1996.  Among these was that the "tote board" - the display of current
betting odds - crashed.

"Betting was never halted during the tote board disruption, but [Ontario
Jockey Club president David] Willmot said it probably cost about
[CA]$400,000 in local betting handle because serious players will not make
large bets unless they can see exact odds.  It was a $35,000 bet in US
currency that crashed the system. The software designed to convert US money
to Canadian in the tote pools could not handle such a large amount."

Hmmm... $35,000.  Do you suppose a bet of oh, say $32,767 might have worked?

Tony Harminc  tzha0@toraag.com


ATM problems in Canada

Richard Akerman <akerman@appliedmicro.ns.ca>
Wed, 30 Oct 1996 21:20:52 -0400
Toronto-Dominion bank's automated teller machines crashed for most of the
weekend, affecting the bank's 2000 machines.  The TD debit payment system
was also down.  In Canada, 80% of the banking is done electronically, and
the 30 million residents have 43 million bank cards.  In a separate item,
some Royal Bank customers had their accounts debited but received no cash.
[There were 1.023 billion ATM transactions in 1995 (about 35 transactions
per year for every person in Canada).]  [Source: Halifax *Daily News* 29 Oct
1996, p. 19.  Reported in Canada by Rob Ferguson, The Canadian Press (CP)
agency, in many papers.  PGN Abstracting.]

Richard Akerman  rakerman@chebucto.ns.ca  http://www.chebucto.ns.ca/~rakerman/


Re: Beating the GRE: What time zone are you in? (RISKS-18.55)

Li Gong <li.gong@Eng.Sun.COM>
Wed, 30 Oct 1996 13:43:23 -0800
The test-beating scenario could actually happen within the same time zone.
To gain entrance to a British graduate school, one usually is required to
take ELTS, which is a British administered English language test that it
similar to the American TOEFL.  ELTS contains 6 exam subjects, including the
normal listening comprehension as well as writing exams where one is asked
to compose a long essay and a short one, in the space of one hour, for two
given themes.  I singled out these two exam subjects because they tend to be
the more difficult ones for native Chinese speakers.  (Oral exam by
interview is probably more difficult, but it is almost impossible to cheat,
except perhaps by hitting on a discussion topic that is favoured by the
interviewer.)

About 10 years ago, the local British council was responsible for
administering the tests, and they had four test sites: Beijing, Shanghai,
Chengdu, and Guangzhou.  They were (and are) in the same time zone but are
hundreds of miles apart.  The British council made things worse (1) by using
a travelling team to conduct the tests, which meant 3 to 5 days delay
between two consecutive tests, and (2) by having only two sets of exam
papers.  The upshot was that snail mail could still allow a few days for one
to fully prepare for the composition tests.  It was said that a year
earlier, an examiner noticed, during listening comprehension, that some
students finished 100% correct papers when the tape was played only half-way
through.

Li Gong, JavaSoft


Re: Beating the GRE: What time zone are you in? (Manny, RISKS-18.55)

Bear Giles <bear@tigger.cs.colorado.edu>
Wed, 30 Oct 1996 18:37:54 -0700 (MST)
> I'm not sure what the charges are for prosecuting such a thing.

Perhaps "falsification of legal documents"?  The government has an obvious
interest if a student is admitted and gets federally backed financial aid on
the basis of fraudulent documents.  Even if the student doesn't get direct
aid, most public schools still receive indirect subsidies.

Bear Giles  bear@cs.colorado.edu


More Personal Information Databases [From PRIVACY Forum Digest 5 19]

Lauren Weinstein; PRIVACY Forum Moderator <lauren@vortex.com>
Mon, 14 Oct 96 13:27 PDT
PRIVACY Forum Digest      Monday, 14 October 1996      Volume 05 : Issue 19
            Moderated by Lauren Weinstein (lauren@vortex.com)
              Vortex Technology, Woodland Hills, CA, U.S.A.
               The PRIVACY Forum is supported in part by the
                 ACM (Association for Computing Machinery)
             Committee on Computers and Public Policy,
          "internetMCI" (a service of the Data Services Division
      of MCI Telecommunications Corporation), and Cisco Systems, Inc.

As you probably have seen over the last few weeks, the topic of personal
information databases has rather suddenly become a "hot topic" in the
mainstream media, propelled partially by the Lexis-Nexis "P-TRAK"
controversy.  The Federal Trade Commission is reportedly considering placing
Social Security Numbers (SSN) and some other related data back into the
"protected" status of the Fair Credit Reporting Act [FCRA] (that is,
removing SSN from the "publicly available" credit header category).  There
are also reports that Congressional efforts that were on track to *weaken*
the FCRA may have been halted or reversed by the resulting public outcry.

But it's worth emphasizing again that we need comprehensive study and
legislation to begin broadly addressing the entire privacy area; it is
simply not possible for these problems to be addressed one service at a
time.

As I pointed out originally, "P-TRAK" does not represent the most onerous of
available databases.  Lexis-Nexis *did* block name to SSN lookups (though
not the reverse), and has provided mechanisms to allow people to request
removal (which may or may not be effective in the long run--time will tell).
But they are at least trying.

There are other services that promote the availability of vast arrays of
personal information that many people would (erroneously) consider private,
with no removal options of any kind available.  It's important to note that
with all the services with which I'm familiar, there is nothing illegal or
otherwise illicit about their operations.  They're distributing "public
record" and other openly accessible data not currently covered by the FCRA
or other laws.  Much of the data comes from public municipal databases, or
from "business transaction" information of the sorts we've discussed
previously, and over which little or no legislative restrictions exist.

It's also the case that there are legitimate reasons why some individuals
and other entities might at times need access to some of the information
contained in various categories of these databases.  There are cases where
some frauds can be prevented or traced through such information.  The
problem is that at present there are no legal requirements placing any
sort of "need to know" on most of this data, so most is accessible
essentially to anyone willing to pay the designated fee, regardless of their
(good or bad) motives.

Many services are providing these sorts of data, some very large and
some small.  Outside of Lexis-Nexis "P-TRAK" with which we're already
familiar, here's information regarding two representative others...

-- "Information America" (http://www.infoam.com)

IA has a nicely laid out web site listing a veritable cornucopia of public
record and other related available data.  I won't even attempt to give a
comprehensive listing here, but just a few of the many categories include:

    Wizard -- master search of all Information America online services

    Asset Locator -- real property, stocks, personal property, etc.

    People Finder -- Address Alert, Credit Bureau Headers,
                 Deceased Records, Neighbor Listings,
             Person Locator, Skip Tracer,
             Social Security Number Tracker, Telephone Tracker,
             Trace a person's residential moves

    Relationship Identifier, and so on...

This is but a small sampling.  In a conversation with their Executive VP,
I learned that, in response to concerns raised by the "P-TRAK" furor, they
have very recently voluntarily removed SSN data from the credit header
output information.  Their web site has been recently updated and no longer
shows SSN as an available data output item.

This puts them in the same category as "P-TRAK" in this respect, in that you
can still *search* for other information using SSN if you already know the
number, but you can't get an SSN from other data via Information America.
I was told that some of their clients engaged in criminal investigation type
work were not at all happy at having the ability to lookup SSNs removed from
everybody's access, since they consider it to be an important investigative
tool.

Information America does not provide a mechanism for persons wishing to be
removed from any of their databases.  First, they feel that the public
record data they supply would be less useful for legitimate purposes if
people could opt-out at will.  Secondly, they say that since some of the
databases are not under their direct control, they do not have the technical
means to provide such mechanisms in any case.

--- CDB Infotek (http://www.cdb.com)

CDB provides a range of services and data very similar to that of Information
America.  However, they have chosen *not* to block access to Social Security
Number data.  According to the customer service representative I spoke to,
you can still look up a person's credit header record based on name,
address, or other data, and obtain their SSN through the service (provided
the SSN is included in that person's database record of course, which would
typically be the case).  CDB also promotes the availability of all
information over the Internet.  No obvious provision for requesting removal
from their databases is apparent.
                    - - -

There are other similar organizations as well.  It's a difficult situation.
In the absence of legislation addressing these issues across the board,
services who take unilateral actions to restrict any class of data feel
that they're putting themselves at a competitive disadvantage compared
with those services who *don't* implement such restrictions.

We need to start working out sensible, logical, and balanced rules and laws
regarding information and privacy, that address the concerns of a wide
range of individuals and organizations.  The longer we wait, and the
more we approach the area in a piecemeal fashion, the more intractable
the problems are likely to become.

--Lauren--


Where Wizards Stay up Late: Book Review

Tom Perrine <tep@SDSC.EDU>
Tue, 29 Oct 1996 17:07:04 -0800 (PST)
    Where Wizards Stay Up Late: The Origins of the Internet
    by Katie Hafner and Matthew Lyon, Simon and Schuster, NY NY 1996
        (ISBN 0-684-81201-0)
        Reviewed by Tom Perrine <tep@sdsc.edu> [See also RISKS-18.29]

The Internet has erupted onto the scene of mainstream consciousness in just
a few short years.  Numerous attempts to "explain" all this technology has
lead to a plethora of books purporting to educate "everyman" about the
innermost workings of this technology.  Out of this morass of
poorly-researched books (and entirely too few good ones) comes something
more interesting: a technological history of the Internet's direct ancestor,
the ARPA network.

Coming seemingly out of nowhere, vaulting from the relative obscurity of a
handful of research facilities into homes and schools across the country and
around the world, the Internet is obviously the most important technological
tool since the personal computer (some would say since movable type).

But where did the Internet come from?  Was it created from whole cloth?  Was
it created by a single company?  Why isn't it run by "The Phone Company?"
What was the ARPAnet?  Just who did invent the Internet, and when, and why?

All of these questions (and many more) are answered by the eminently
readable book _Where Wizards Stay Up Late: The Origins of the Internet_.
This books could be dismissed as simply _The Soul of a New Network_, but
that would be a mistake.  This book is more readable, yet more technically
complete and accurate than Kidder's _The Soul of a New Machine_.

Katie Hafner and Matthew Lyon have successfully explained the origins of the
technology that millions now depend on and take for granted every day.  They
take the reader on a journey that begins in the early days of the Cold War
with the launch of Sputnik, and ends with today's commercial on-line
services, and ubiquitous electronic mail and World Wide Web addresses.

If you doubt that "the Net" has become important to average consumers,
consider these questions: Has anyone seen a recent television commercial or
magazine advertisement without an "http" in it lately?  Why did the Cable
News Network (CNN) have as its lead stories the recent network outages of
America Online and BBN Planet that left literally millions without Internet
access for more than a day?

Along the way, we are treated to the dreams of visionaries and charlatans,
academics and bureaucrats, scientists and engineers, who shared the hope of
using technology to connect people to people.

The story is organized chronologically, yet always sets the technology in
the context of the people and the culture of the times.  The book focuses on
the earliest period of the ARPAnet, the original computer network research
project funded in the 1960s by the US Department of Defense.  This period is
the least known, and the information about this period the most important to
preserve at this time, while the persons involved are still around to tell
(and debate) their stories.

This book is a first-class piece of historical detective work, piecing
together developments at laboratories across the country and around the
world, all of which dovetailed to produce the world's first
geographically-distributed computer network.

The first chapters are devoted to the origins of the Advanced Research
Projects Agency (ARPA) itself, set in the days following Sputnik, and
America's technology "wake-up call".  The early advocates of "computer
communications" are introduced, including Bob Taylor, Joseph Licklider
("Lick"), and Larry Roberts.

This book attempts (and mostly succeeds) in tracing the engineering
decisions that shaped the ARPAnet's technology (and culture).  The early
debates of circuit-switched vs. packet-switched designs, centralized (star)
vs. distributed (mesh) are all examined and explained in accessible, yet not
over-simplified terms.

The origins of Bolt Beranek and Newman (BBN),and the people who worked there
are described in some fascinating detail.  Who would imagine that a
consulting company that was formed to perform acoustical engineering for new
buildings would become the builders of a computer network?  The trials and
tribulations of the "IMP Guys" that led to the creation of the first network
"router", the ARPANET Interface Message Processor (IMP), introduces two
people who would continue to to connect people and computers: Willie
Crowther (original author of "ADVENTURE"), and Bob Kahn, who started the
Strategic Computing Program, which is the more formal name for the
"Information Superhighway" program of the U.S. government.  The late nights,
and the eradication of "the bug" on the eve of the first IMP's shipment from
Cambridge to California are all recounted in a no-nonsense,
technically-savvy style.

Later chapters describe the activities at SRI, the original Network
Information Center (NIC), and the culture and people who decided that a
network standards document should be a "Request For Comments" (RFC).

These RFCs, and a culture of openness have been blamed (or praised) for the
demise of the International Standards Organization (ISO) Open System
Inteconnect (OSI) network protocols; the closed, agonizingly slow process of
ISO standardization process was continually "overcome be events" as the
ARPANET folks pushed the envelope with "rough consensus and running code".

Along the way we meet the first RFC, by Steve Crocker, titled simply "Host
Software", followed by the first higher level protocols, documented by Jon
Postel, Vint Cerf, the "MsgGroup" and the network's first "flame war" (over
e-mail standards), the now-infamous "header wars".

The ARPANET's direct contribution to Artificial Intelligence research,
operating systems (including UNIX), and human communication are all explored
as well.

It's an interesting journey, told through the eyes of the pioneers that
blazed the trail.  But make no mistake, this book is about the people behind
the technology as much (or more) than about the technology itself.  Having
essentially "grown up" on the net (my first ARPANET host account was active
in 1976, when I was in high school), I was fascinated by the stories of the
people who made all this communication possible.  This book has filled in
all the background of the happenings that I was too naive (or busy with
school :-) ) to understand at the time.

The authors of this book have reached back to the original sources, they
have spoken to and interviewed many of those who were directly responsible
for the work described.  In many cases the authors have reached into the
ARPA/IPTO Oral History project tapes and distilled this collection of
interviews into a seamless, coherent picture.

This book is about the people who invented the technology and culture of the
Internet, the legacy of practical engineering, and "rough consensus and
running code."

Tom E. Perrine (tep@SDSC.EDU) | San Diego Supercomputer Center
http://www.sdsc.edu/~tep/     | Voice: +1.619.534.5000

Please report problems with the web pages to the maintainer

Top