The RISKS Digest
Volume 12 Issue 34

Monday, 16th September 1991

Forum on Risks to the Public in Computers and Related Systems

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

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Network Security Lacking at Major Stock Exchanges
"Planted" data in databases
Re: RSA vs. NIST
Greg Rose
Steve Bellovin
Dan Bernstein
Kevin McCurley
Re: Export controls on workstations
Hank Nussbacher
Lars-Henrik Eriksson
John Mainwaring
RISKS of trying to get hard facts [OS/2]
Conrad Bullock via Gideon Yuval
RISKS (yet again) of not enough data
Bill Gunshannon
Re: +&*#$
Dave Roberts
Re: Multics/UNIX Lessons
Dick Karpinski
Info on RISKS (comp.risks)

Stock Exchange Risks

"Peter G. Neumann" <>
Mon, 16 Sep 91 14:28:21 PDT
          "Network Security Lacking at Major Stock Exchanges --
            GAO cites susceptibility to outages, tampering"

``The General Accounting Office (GAO) found a total of 68 computer and network
security and control problems at five of the nation's six major exchanges
during reviews it conducted this past year for the Securities and Exchange
Commissions.  The lack of adequate controls at the five stock markets could
impair their ability to maintain continuous service, protect critical computer
equipment and operations, and process correct information.''  The worst three
in terms of numbers of problems were the Midwest (24), Pacific (18), and
Philadelphia (18) exchanges, which were all faulted for their inadequate risk
analysis.  The biggest problems were in the areas of contingency planning and
disaster recovery.  The NY and American stock exchanges came off relatively
well.  [Source: article by Wayne Erickson, Network World, 16Sep91, pp.23-24.]

"planted" data in databases

Mon, 16 Sep 91 09:20:21 xxT
A previous poster discussed how a firm would send out false traffic reports
over 2-way radios to confuse a rival firm.  It is indeed the case that planting
of false data to detect copying or misuse of information has a long, long
history.  In fact, many companies explicitly tell their customers that there is
false data to discourage misuse, while others don't advertise the fact but
don't make a secret of it either.

For example, in the mailing list industry, it is common practice for some
names/addresses to be "dummies" that are people in the pay of the mailing list
firm.  These addresses are used to try detect if the terms of list use (e.g.
one-use only) are being violated.  If two many mailings show up at one of those
addresses from the company, the list firm knows there's a problem.  Of course,
this also means that the company sending out the mailings is wasting some money
sending materials to those "planted" addresses.

Another field where this technique is used involves maps.  Street maps may show
little side streets that don't really exist.  If a competing map shows up with
the street... blammo!  Larger scale maps may show tiny towns that don't really

It goes on and on--all manner of databases may have planted entries that are
used for detection purposes.  Of course, false entries aren't the only method
to do such detections--other methods involve use of unusual spellings, "typos"
that are really intentional, unique word orderings, etc.

                                                   [Even the RISKS Forum?  PGN]

Re: RSA vs. NIST (Slone, RISKS-12.33)

Greg Rose <>
Mon, 16 Sep 1991 14:39:15 GMT
>... presumably these are logarithms that have truncated ...

They are not truncated logarithms.

Both schemes rely on arithmetic in a finite field (modulo n arithmetic where n
is the product of two large primes) being RSA's operating field. If a**b .eq. c
(all modulo n), then finding a given b and c is called the discrete logarithm
problem. For RSA, it turns out that you can do it in (at least) two ways: one
is brute force, and for sufficiently large numbers is infeasible, and the other
is factoring n.  However, the problem being solved is still the discrete
logarithm problem for both of them.

> ...

It is possible that my recollection is dated, but to my knowledge the RSA
system is still the only known "reversible" system, where the private and
public keys can be used for both privacy and authentication. Assuming that the
other system doesn't allow this reversible use, the standard is significantly
less useful than it could be.

>...  These advances have forced made it necessary to
>increase the length of encryption keys for the RSA method.

However, each extra ten digits in the key at least doubles the brute-force
difficulty. This behaviour seems able to keep ahead of hardware advances fairly

(I have no relation to RSA Inc, other than admiration for the elegance and
utility of the system.)

Greg Rose - Chance Airlines      (914) 945 1179

RSA vs. NIST (digital security standards) (Slone, RISKS-12.33)

"Steven M. Bellovin" <>
Sun, 15 Sep 91 23:21:36 EDT
What NIST has proposed is not an encryption standard, but a digital signature
standard.  Digital signatures provide authentication but not secrecy.  That, to
my mind, is the major reason this scheme was proposed instead of RSA.  Dating
back at least to the adoption of the Data Encryption Standard, it's been
obvious that (at least some part of) NSA is hostile to the widespread
deployment of encryption technology.  RSA inherently provides secrecy as well
as authentication; the NIST scheme provides only the latter.  (Incidentally,
discrete logarithms are logarithms in a finite field, such as the integers
modulo some prime.  For example, given that c = (a^b mod p), b would be the
discrete logarithm.  It is indeed a hard problem to find b, though not as hard
as had once been thought.  Put another way, p needs to be much larger than was
realized a few years ago.  At least one important authentication system based
on the discrete log problem has been cracked.)

Numerous aspects of the NIST proposal are controversial, including the claim
that it is free from (other) patents.  Other oddities: signing a message in
this scheme is less expensive than verifying a signature.  That seems strange;
for many applications, very many parties will need to validate a message that
will be signed only once.  (I doubt that there is any real RISK to forged RISKS
messages, but most people I know would be much happier if they could validate
security fix announcements from CERT.)

The claim has also been made that the scheme either has a trapdoor, or is
insufficiently secure against a determined attack.  Without going into details,
the nature of the standard is such that an attack on the system per se would
permit solution of everyone's key; with RSA, on the other hand, each
public/private key pair must be attacked individually.  Note, though, that this
is a signature mechanism, not a privacy mechanism; finding a party's private
key allows you to impersonate that party in network communications, but does
not disclose their secrets without an active attack.  We can all imagine the
kinds of mischief that can result from forgeries — but NSA is generally more
interested in listening than in speaking.
                                                --Steve Bellovin

RSA vs. NIST (digital security standards) (Slone, RISKS-12.33)

Dan Bernstein <brnstnd@KRAMDEN.ACF.NYU.EDU>
Mon, 16 Sep 91 06:18:29 GMT
In RISKS-12.33, Tom Slone comments on the NIST DSA public-key proposal.
Discrete logarithms are not logarithms which have been ``truncated to a
finite but large length.'' Can you tell me what power I have to raise 3
to in order to get 77710 mod 157931? That's a discrete logarithm. Slone
then repeats a statement from Jim Bidzos (president of RSA Inc., and of
Public Key Partners) saying that the NIST DSA is weak, and adds ``there
is some merit in his statement since knowledge of prime-factoring has a
long mathematical history,'' while discrete logarithms are ``presumably
a new sub-field.'' Actually, Bidzos's claim is entirely unjustified. We
have learned a lot about both factoring and discrete logs over the last
thirty years or so, and at this point there's no reason to believe that
one will be easier than the other. The NIST DSA has the clear advantage
of being free of patents. For that reason alone I will use it.

   [I usually unjustify short or long lines to save paper/screen length
   or make them readable on 80-character screens, but left this message
   as received because it was remarkably right justified without having
   any extra blank spaces inserted!  With such arguments you can have a
   message that is entirely justified even if the contents are entirely
   unjustified.  Just if I tried ... PGN]

Re: RSA vs. NIST (digital security standards) (Slone, RISKS-12.33)

Kevin S. McCurley <>
Mon, 16 Sep 91 13:37:26 MDT
The recent posting by Tom Slone on the NIST proposal for a digital signature
standard contained some unfortunate mistakes that I would like to correct.

First of all, the NIST standard is for digital signatures - not encryption.  If
you don't know what a digital signature is, then briefly it is a means to
"sign" an electronic document in much the same way that you would sign a paper
document.  Its purpose is to protect the authenticity of information, not the
privacy of information.  It provides much more than a hash or checksum, since a
hash can be produced by anyone, but a digital signature can only be produced by
the legitimate signer.

Second, the discrete logarithm problem is not something that was plucked out of
thin air by NIST.  In fact, discrete logarithms were applied to cryptography
before factoring, because the discrete logarithm problem was used by Diffie and
Hellman in their original paper on public-key cryptography, whereas factoring
came along the following year in the RSA paper.  Certainly the problem of
factoring is old - but the discrete logarithm problem has also been studied by
computational number theorists going back at least to the time of Gauss in
1801.  For more information on the discrete logarithm problem, see "Computation
of Discrete Logarithms in Prime Fields", by B.A.  LaMacchia and A.M. Odlyzko,
Designs, Codes, and Cryptography, volume 1, (1991), 47-62.  Also cited there is
a survey I wrote in 1990: "The discrete logarithm problem", pages 49-74 in
"Cryptology and Computational Number Theory", volume 42 of Proceedings of
Symposia in Applied Mathematics, American Mathematical Society, 1990.

Finally, I would like to point out that there has been relatively
little progress made on the problem of "factoring primes".  More
progress has been made on the problem of factoring composites...

Perhaps the biggest risk is in forming opinions based on incomplete

The NIST standard itself is based on a method published by ElGamal in 1984, but
incorporates several innovations that improve its performance.  The NIST
proposal included a call for comments, which appeared in the Federal Register
of August 30.  Interested parties have 90 days from that date to send their
comments to NIST.
                              Kevin S. McCurley, Sandia National Laboratories

Re: Export controls on workstations (Cooper, RISKS-12.31)

Hank Nussbacher <HANK@VM.BIU.AC.IL>
Sun, 15 Sep 91 09:21:52 IST
>The computer-based RISK here is based upon permitting morons to make decisions

The risk here is trying to use technology as a pawn for politics.  Israel has
for the past 3 years tried to obtain export licenses for a vector processor
upgrade for a 3090-200.  Articles about this have appeared in the Washington
Post and the NY Times.  There was a period of a year where we could not get 486
PCs until the Far East started producing them and then suddenly the export
license ban was "relaxed".  We have had cases of Vax 4100s being restricted and
as the compute curve moves upward we never know what we can obtain and what
will be restricted.  We looked into buying a Japanese mainframe but it turns
out that Japan and the USA have an export agreement - whereby if the USA says
no to one country, Japan has to abide by that agreement.

The risk here is not of morons making decisions but of using computers as a
carrot for political policy decisions.  The USA government can't control
weapons making their way to various terrorists groups so there is absolutely no
possible way for the USA government to restrict computer technology to these
same terrorist groups.  The reason these decisions are made is to restrict
access to countries who wish to use these systems for education or research but
who don't follow the exact views of the current adminstration.

Hank Nussbacher, Israel

P.S.  The views expressed above are my own and do not reflect the views of my
employers nor of the government of Israel.

    [Note: I normally delete all disclaimers, particularly jokey ones,
    hoping that they are adequately covered by the masthead generic disclaimer.
    This one seemed appropriate, however.  PGN]

Re: Export controls on workstations, ... (Leichter, RISKS-12.33)

Lars-Henrik Eriksson <>
Mon, 16 Sep 91 09:00:46 +0200
> ...  The US could probably require US companies to place
> appropriate restrictions in their licensing agreements.

They U.S. not only could, but the already do! Export licenses are needed for
all high performance U.S. CPUs. These licenses carry the restriction that the
equipment may not be reexported without U.S consent.

Lars-Henrik Eriksson, Swedish Institute of Computer Science, Box 1263
S-164 28  KISTA, SWEDEN   (intn'l): +46 8 752 15 09

Re: Export controls on workstations ... (Leichter, RISKS-12.33)

John (J.G.) Mainwaring <>
16 Sep 91 15:02:00 EDT
I think Jerry Leichter's response to the thread started by John Markoff and
PGN's posting, Export controls for workstations, may be missing the point of
the original DoD proposal.

If the original posting and its followups had been specifically about sales to
terrorist organizations or undesirable foreign governments, I might have agreed
with Jerry's posting.  Since the IRA does not normally apply directly for
export licenses for Sun workstations, the DoD proposes to restrict ALL exports
of workstations to reduce the likelihood of the IRA getting one from their
Belfast Radio Shack.  Jerry's choice of the South African security forces as an
example also moves the discussion on in an interesting way.

If Jerry chooses to argue by analogy - always a RISKy endeavor - lets try
another one.  We disapprove of international terrorists robbing banks, so we
should shut down the export of all equipment used in banks overseas.  Of
course, since the disclosures about the BCCI, it appears that international
terrorists don't rob banks, they own them - but that's the risk of not really
understanding the problem.

I admire Jerry's wish to use the influence the US has in technology to bring
about worthy goals.  In cases such as the sale of armaments where the goods
being sold have no peaceful use, his approach seems feasible.  However, I think
his perception of American influence in the world of workstations and UNIX is
not shared by those of us who have spent most of our lives elsewhere.  The rest
of the world is willing to license American workstations and UNIX because they
perceive the cost of developing alternatives not to be worth the effort.  This
is based on widespread agreement that these things would not be easy to
replace.  If American policy makes dependence on American products unacceptable
to the rest of the world, it will create an opportunity for competition that
would not have arisen purely on technical merit, and this will mean jobs in
Singapore or Malaysia or wherever.  Of course, views on the goodness of this
outcome will vary depending on where you live.

As I said above, the rest of the world might applaud if the US significantly
reduced its arms exports - to everyone - but it tends not to understand the
logic behind placing controls on the export of Kleenex because it has been
discovered that international terrorists are unusually susceptible to colds.

RISKS of trying to get hard facts

"Gideon Yuval 1.1114 x4941" <>
Mon Sep 16 08:28:36 PDT 1991
         [Forwarding from Gideon Yuval, Microsoft, 1 Microsoft Way,
         Redmond, WA 98052-6399 206-882-8080]

Newsgroups: comp.os.os2.misc
Subject: 'OS/2 Rumours' Clarification
From: (Conrad Bullock)
Date: Wed, 11 Sep 1991 12:11:16 GMT
Organization: Dept. of Comp. Sci., Victoria Uni. of Wellington, New Zealand.

Back on September 2nd, I posted an article about some rumours which I had heard
from an IBM dealer, in relation to pricing and release dates for OS/2 2.0.

As it turns out, he was in no way speaking for IBM officially, and any
information that he passed on to me was purely conjecture on his part.  Due to
the numbers that he mentioned, and in the absence of any mention to the
contrary, I took that information at face value, and assumed it to be
relatively reliable.

Unfortunately, I took the route of posting the information that I had here, in
order to verify whether it was true or not. (The subject line was "'Rumours'
about OS/2 2.0 release", and I ended my message with "Can anyone confirm or
deny any of this?").

The message caused some concern to IBMers, and I can understand why.
Larry Salomon, Jr. passed on the message to John Tiede, who said:

> Larry, If you could respond on USENET that the information was not
> correct and IBM is going to inform the misinformed IBM party (note - no
> witch hunt, as we only want to insure accurate information and not deter
> open dialogue, which is so important in this evolving electronic world,
> he said stepping down off the soap box......).  Thanks for your help in
> this.........

Unfortunately, it has developed into a witch-hunt in a large way at the New
Zealand end of things. I received a call from IBM New Zealand today, asking for
a categorical statement saying what I had been told, and by who. The dealer
concerned, and at least one person at IBM Wellington really are in quite
serious trouble, and the relationship between the parties concerned, including
myself, is strained, to say the least.

I have spoken to the dealer and the IBMer concerned since, and having just been
hauled over the coals, they were understandably angry at me — the dealer even
spoke to my boss, concerned that it was some form of malicious message aimed at
`making a name for myself'.

It sounds as if umbrage was taken at my mention of NZ pricing policies, and any
parallel that I was trying to draw between NZ and US pricing - for that I am
sorry, and for the information about release dates and final prices.

Anyway, I would just like to stress that the rumours which I posted
here were just that - rumours. There was no malice on my part. It was
essentially a misunderstanding on my part of some conjecture from the
dealer concerned. There was no IBM involvement, and I am dismayed to
hear that an IBMer has got into trouble over my posting. I am writing
letters to try and help his situation.

For some real misinformation about OS/2, try this message, posted in today:

> I also forgot a new version of OS/2 is coming out about the same time,
> it is said to co-exist with DOS.  It will run under MS-DOS.

Perhaps this sort of misinformation is less dangerous, as it's so obviously
incorrect, while 'feasible' misinformation is a bit more insidious?

I really want OS/2 to succeed as much as anyone. I am frustrated by the
disinformation about OS/2 which is spread by many channels, especially in the
press, and I did not wish to contribute to that.

I am excited by the impending release of OS/2 2.0. I hope it takes the market
by storm, and becomes the success it deserves to be - programmers the world
over (not to mention the users), will be eternally grateful. With such a
product on the horizon, and as yet, no official words from IBM on features or
release dates, it should be of no surprise to IBM that there is a lot of
speculation on what will or will not be included, and when, especially amongst
the OS/2 faithful.

I should have perhaps asked IBM NZ directly for clarification on these
points, although they have generally not been much help in the past -
I assume that they are not allowed to tell me anything anyway.

In summary:

- There was a misunderstanding - the dealer should have made it clear
  that he was speculating, I should not have taken the information as
- I shouldn't really have posted the information here.
- An IBMer is in trouble, and he shouldn't be.
- I probably should not have passed on the dealer's name and details
  to the IBMer concerned, but in my naivity, I did not imagine that it
  would snowball in quite this fashion.

Conrad Bullock, Victoria University of Wellington, New Zealand Fidonet  3:771/130

The RISKS (yet again) of not enough data (Deibele, RISKS-12.32)

Bill Gunshannon <>
Mon, 16 Sep 91 12:33:04 EDT
  I think (based on my personal experience) that a much bigger RISK is that
this type of media (i.e., Email, Computer Conferencing) might find its use
curtailed or, in the case of schools, restricted, based on a concept that has
not been researched enough to justify it.

  I believe that the apparent hot-headedness seen in Email, BBSes and
USENET are only signs of an immature communications media and do not
accurately reflect what we can expect in the future.

  My own experience tends to bear this out.  When I was first introduced
to USENET and NEWS, in 1982, I was very quick to flame people for the
slightest remark with which I didn't agree.  Today, if I come across
something that I feel requires a response, I save the offending message
and give the whole thing some thought.  Somewhat akin to stopping to count
to 10.  In 95% of the cases, I then decide it isn't worth raising my blood
pressure about and throw the article away.

   As more and more people become exposed to this form of communications, I
feel it will develop the same mores and customs as other more conventional
forms of communication.

   After all, we don't consider the telephone to be a disadvantage to
communication even though we may receive the occasional obscene phone call.

Bill Gunshannon, University Computing Systems, University of Scranton,
Scranton, PA

Re: +&*#$ (Morris, RISKS-12.31)

Dave Roberts <>
Mon, 16 Sep 91 11:19:33 GMT
In RISKS-12.31 in Re: +&*#$ (Moore, RISKS-12.21) Mike Morris writes:

> ... Once I was pulled over by a cop who was as fascinated as
> I was when my plate wouldn't come up and we spent some time with his patrol
> car terminal discovering this quirk. [...]

It seems to me that we are all missing the risk to society here and thinking
only of the individual.

The society we live in gives each motor vehicle a <supposedly> unique id
so that those who need to do so can identify that vehicle easily.

The society we live in takes money from each and every one of us to spend on
the common good.

Some of that money pays policemen to prevent and/or detect and recover from

Society allows people to advertise themselves by writing their name, slogan,
etc as big as they like on their vehicles - many elements of society do that
and the results can be seen driving down any road any day.

I think Mike (and many others - nothing personal) confuse the need for a
unique vehicle id with their wish for self-advertisement to the detriment
of society in general.

The way to do what he appears to want is to paint his call-sign in big letters
on the side of his vehicle and accept a standard issue vehicle number for
the tiny little plate that is there for those who "need-to-identify".

Or am I missing something??
                                           David Roberts

PS. I think he also owes all the other John Does paying taxes for the time
of one cop and one car and one computer system for the wasted effort caused
by his insistence on a misuse of vehicle number plates;  the RISK is loss
of availability of a cop who could be doing something useful instead.

PPS. Whether traffic cops in patrol cars EVER do anything useful is not a topic
for this newsgroup - we all pay them so we all think that they do!

Re: Multics/UNIX Lessons (Edward Rice, RISKS-12.25)

Dick Karpinski <>
Fri, 13 Sep 91 17:43:58 PDT
Since the people involved with the initial creation of UNIX are very much alive
today, we could probably get the truth.  Mr. Rice's version is very different
from the one I tell.  I claim that far from Bell Labs deciding to create a
variant of Multics, Ken Thompson used a neglected PDP-7 lying about in a store
room to build a little system to permit him to play a little space-war.  It
might actually be that before it could be said to be even the origin of UNIX,
it had become a vehicle to test some of Ken's theories about building
appropriate systems.  Even so, I'm sure that years passed before the labs
decided to use and support the system.

To keep this short, I believe the development of the UNIX system was more like
the stories James Burke tells than like the steady, intended progress so often
reported in textbooks.
                                              Dick Karpinski

   [I try not to interject my own historical perspective into too many messages
   but at this point I might as well interject that Dick is indeed closer to
   the truth — except for the space war.  By the way, another interesting
   historical perspective is provided by F.J. Corbato's Turing Address Lecture
   in the September 1991 CACM, relating to CTSS, Multics, and (incidentally)
   Ken Thompson and UNIX.  PGN]

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