HDTenEightyP/NetNews huggingface dataset:
From: who@gandalf.UMCS.Maine.EDU (William H. Owen)
Subject: Re: Are DES restriction even logically sound?
Organization: University of Maine Department of Computer Science
Date: Mon, 7 Sep 1992 22:56:15 GMT


	There is a nice version of DES in pascal included in "Computer Networks"
by Andrew S. Tanenbaum. Anyone have a version of DES with a 128 bit key size? Or
alternative choices for S-boxes? Or just maybe the NSA doesn't want you to crypt
something that the gov't can't uncrypt.
From: Graham.Shaw@newcastle.ac.uk (G.D.Shaw)
Newsgroups: sci.crypt,alt.security
Subject: Re: Are DES restriction even logically sound?
Date: 6 Sep 92 13:08:29 GMT
Organization: University of Newcastle upon Tyne, UK NE1 7RU

In article <1992Sep5.164646.21443@uwm.edu> markh@csd4.csd.uwm.edu (Mark) writes:
>
>   Supposing I have a complete description of DES in text form, and I split it
>into 8 parts, with file N containing every 8th character modulo N.
>
>   If 100 people each decide to post one of these files (they make a random
>choice without knowing about the other 99 people even being there), and posts
>it to a place that can be publically accessed outside the US, then have any
>restrictions on DES been violated?  If so, who violated them?  How?

You can do far better than that:

1. Split the article using the original and seven one-time pads (which must
   have good statistics), such that
   DES = A Xor B Xor C Xor D Xor E Xor F Xor G Xor H

2. Hide each of A..H in a form such that they all have some use other than
   re-constructing the original DES code.  (For example, embed them as
   noise in the low-order bits of a picture).

This has the advantage that in isolation, none of the messages transmit
any information at all, and even with all eight it is impossible to prove
which was the original and which were merely keys.

To confuse matters further, add an extra step:

3. HARMLESS1 = A Xor B Xor C Xor D Xor I
   HARMLESS2 = E Xor F Xor G Xor H Xor J

(where HARMLESS1 and HARMLESS2 are meaningful and useful, but of no
significance re. export laws).  Then publish I and J.

Note, however, that as has been pointed out by another poster, US export
laws are concerned with computer programs and hardware devices, not mere
descriptions of DES.

I would also note that whereas this (and several other intellectual
property laws) suffer from a confusion between data flow and information
content, I would not trust the US authorities to worry too much about
legal or indeed logical nicities if they really wanted to get you.

Graham Shaw
Department of Physics, Durham University, England
Xref: sparky sci.crypt:3244 rec.arts.movies:27777
From: krazykid@csa.bu.edu (Ernest Kim)
Newsgroups: sci.crypt,rec.arts.movies
Subject: Re: "Sneakers" -- action/adventure movie about Cryptography
Date: 15 Sep 92 12:16:12 GMT
	<1992Sep4.205842.12303@qualcomm.com>
	<1992Sep10.034159.1617@qiclab.scn.rain.com>
	<1992Sep14.150328.11198@b11.b11.ingr.com>
	<1992Sep15.095017.27880@m.cs.uiuc.edu>
Followup-To: sci.crypt
Organization: Boston University Computer Science Department
In-reply-to: kadie@herodotus.cs.uiuc.edu's message of 15 Sep 92 09:50:17 GMT

In article <1992Sep15.095017.27880@m.cs.uiuc.edu> kadie@herodotus.cs.uiuc.edu (Carl M. Kadie) writes:

   I think the biggest flaw in "Sneakers" is that it treats information
   (the decryption program) as a physical object (by actually putting it
   in a physical object).

   In a more realistic movie, everyone would be searching hard disks for
   copies of the program rather than the Bay Area for a box. The movie
   would have ended when someone posted the "Too Many Secrets" program to
   sci.crypt.

In a more realistic movie, they wouldn't be using modems where you put
the telephone mouth piece on a suction cup to make a connection with a
computer.  How about using a logic probe to connect the black box to
the computer??  These aren't meant to be flames, just realism
comments.  I really liked the movie because it was funny and kept me
entertained, not for it's representation of technology.  

Ernie
krazykid@csa.bu.edu

PS:  Don't watch this movie with four or more computer science
students together.  It sorta ruins the movie for you and the people
around you.  

PPS: It's amazing how many people will believe whatever shows up on
the screen.  The people sitting believe us were saying something like
"I can't believe that they can do that," or "I didn't think that was
possible," throughout the entire movie.  It was a source of a minor
chuckle for us.  :)
From: heim@peanuts.informatik.uni-tuebingen.de (Gerald Heim)
Subject: Re: Are DES restriction even logically sound?
Organization: organisiert? ich? ach was!
	<1992Sep7.051916.16197@qualcomm.com>
Date: 7 Sep 92 13:57:42



Maybe DES itself is against some law? :-> *flameflame*

Newsgroups: sci.crypt
From: craig@jido.b11.ingr.com (Craig Presson)
Subject: Re: "Sneakers" -- action/adventure movie about Cryptography
Reply-To: craig@jido.b11.ingr.com
Organization: Intergraph Corporation, Huntsville, Alabama
	<1992Sep4.205842.12303@qualcomm.com>
	<1992Sep10.034159.1617@qiclab.scn.rain.com>
Date: Mon, 14 Sep 1992 15:03:28 GMT

In article <1992Sep10.034159.1617@qiclab.scn.rain.com>
leonard@qiclab.scn.rain.com (Leonard Erickson) writes:
   karn@qualcom.qualcomm.com (Phil Karn) writes:

   >It sounds like that scene was written by the same guy who did the
   >climax of "War Games". Remember how the computer (Joshua?) cracked the
   >missile launch code ONE CHARACTER AT A TIME?

   >I wish I could find a bank with a vault whose combination lock worked
   >that way.
Saw the movie yesterday. I, too, really wish they had gotten some competent
technical advice. I don't think a novella based on that script could
have gotten published in any major SF magazine (maybe I give them too
much credit, too, but that seems to me to be the minimum standard that
"Sneakers" should meet). I think what they did was make the
technobabble convincing enough for all but the hardcore computer geeks
in the audience, and leave it at that. It made suspension of
disbelief very hard. I was willing to give them a black box that
cracks RSA systems, as far-fetched as that is (and as easily defeated,
at least if you expect fully automatic operation) -- since at least they
went to the effort to relate it to number theory (and I thought the
lecture was done well -- they knew they couldn't make it convincing if
you could hear all of it, so they cut in and out tracking Matt
Bishop's distracted attention, and it sounded just like a math lecture
that you're half asleep in :-). A much better job was done on the 
standard spy stuff, IMO, except that having Bishop and Associates able
to find out that much stuff about that supposedly well-protected
building by remote E&M analysis was a bluff -- I suppose they
never heard of Tempest?

And finally, the last little plot twist at the very end was dimwitted
and in poor taste several different ways. I will not spoil, I will not
spoil ...

I still managed to enjoy the movie, but I don't think I'd watch it
again -- unless I wanted to play "how many technical flaws can you
spot"!

-- Craig
From: trt@duke.cs.duke.edu (Tom Truscott)
Newsgroups: sci.crypt
Subject: Re: Secure password generation
Date: 16 Sep 92 03:36:17 GMT
Distribution: na
Organization: IBM RTP


This is not a secure password generator!
If there are no arguments it seeds the pseudo-random number generator
with one of 32k different values.
Trial decryption is thus trivial.
(If there *are* arguments it probably seeds from an even smaller range.)

You don't need a better pseudo-random number generator,
you need a better source of randomness.  A high-resolution clock
might give you 32 unguessable bits, but that is not enough.
Another possibility is to have the user type something and measure
inter-character times with a busy loop:
	/* this is a crude example */
	for (8 times) {
		ask user to type something
		for (i = 0; no_keypress; i++)
			;
		the low-order value of "i" is probably quite random now
	}
This produces 64 unguessable bits (one might hope) that could be used
to seed a good PRNG, or probably even a crummy one by periodically doing:
		srand(rand() ^ some_of_the_unguessable_bits);

It is amazing how easy it is to break most of the posted password generators.
But then again, it is an easy trap to fall into.
Someone please post a really strong generator,
and try and make it widely available, and become famous.

Tom Truscott
From: sasghm@theseus.unx.sas.com (Gary Merrill)
Newsgroups: sci.logic
Subject: Re: Set Theory and Theology
Date: 9 Sep 92 13:34:01 GMT
Distribution: sci.logic sci.philosophy.meta
Organization: SAS Institute Inc.
Originator: sasghm@theseus.unx.sas.com


In article <1992Sep8.204819.316@guinness.idbsu.edu>, holmes@opal.idbsu.edu (Randall Holmes) writes:
|> 
|> 
|> Please note that the existence of the set of all natural numbers is
                                         ^^^
|> sanctioned by one of the Fathers of the Church.  Note the use of

This is not obvious.  I am suspicious of the translation, you clever
promulgator of Platonism.

|> Every number is defined by its own unique character, so that no number
|> is equal to any other.  They are all unequal to one another and
|> different, and the individual numbers are finite, but as a class they
                                                              ^^^^^
Class?  Do you have the Latin here?

|> Never let us doubt, then, that every number is known to him 'whose
|> understanding cannot be numbered'.  Although the infinite series of

Of course, this doesn't require there to be a set of same.
-- 
Gary H. Merrill  [Principal Systems Developer, C Compiler Development]
SAS Institute Inc. / SAS Campus Dr. / Cary, NC  27513 / (919) 677-8000
sasghm@theseus.unx.sas.com ... !mcnc!sas!sasghm
From: cxm7@po.CWRU.Edu (Colin Mclarty)
Newsgroups: sci.logic
Subject: Re: Set of all sets + correcting MZ's syntax
Date: 6 Sep 1992 18:11:55 GMT
Organization: Case Western Reserve University, Cleveland, OH (USA)
Reply-To: cxm7@po.CWRU.Edu (Colin Mclarty)
NNTP-Posting-Host: slc12.ins.cwru.edu


In a previous article, ziane@nuri.inria.fr (ziane mikal -) says:

              (much else deleted)
>
>Also, I don't know anything yet about categories. I have heard
>though that the category of all the categories is not a pb.
>Does category theory have similar paradoxes though ?
>
>
>Mikal Ziane.
>

	The category of categories is an open problem.  Set theoretic
approaches to it are not promising.  I have a tiny note in _JSL_ _57_
(pp.555-6) showing in effect that if you define categories set
theoretically in a set theory which includes a set of all sets, then
you can get an actual category of all categories but it will have
such terrible properties as to be useless.  (That does not mean that 
set theoretic considerations can not bear on the question, but 
straightforward set theory will not solve it.)

	The category of categories can be approached categorically too.
The classic source is by Lawvere, "The category of categories as
a foundation for mathematics" in _Proc. of the La Jolla conference on
Categorical Algebra", Springer-Verlag 1966 (pp.1-20).  More recently 
there is my own "Axiomatizing a category of categories" in _JSL__56_
(pp.1243-60).  Both briefly discuss what would be needed for "a
category of ALL categories".

	On a categorical approach a "category of ALL categories"
would presumably use Benabou's approach via fibrations (see Benabou 
"Fibered categories and the foundations of naive category theory" 
_JSL__50_ pp.10-37).  It would require a kind of universal fibration.  
It would require a universe of categories and functions, one of whose 
functors was a fibration such that:

	Every category in that universe is a fiber of that fibration

	Every functor in that universe appears as the functor
		between fibers induced by some arrow of the base
		of the fibration.

That second condition seems to me to want an elegant statement, and I
don't have one for it.

	It seems very unlikely that such a "category of all
categories" will give anything like a Russell's paradox--in part
because we never say EXACTLY WHAT any category is MADE OF.  Such
talk is nonsense on a categorical account.  So we can not define
a paradoxical category by giving an impossible requirement on the
categories and functors it should be MADE OF, the way we do for
elements of the Russell set.

	Such a fibration might lead to some kind of cardinality
paradox.  I am inclined to doubt it.  But I will speculate no more
here.  The problem remains open--even as to its exact statment.

Colin McLarty

	 
Newsgroups: sci.logic
From: lma@dayton.Stanford.EDU (Larry Augustin)
Subject: Linear Temporal Logic verifiers generating counterexamples??
Organization: DSO, Stanford University
Date:  5 Sep 92 00:18:52 GMT

I'm looking for algorithms for producing counterexamples for linear
propositional temporal logic (LPTL) verification.

That is, given two LPTL formulae p and q, check if (p implies q) is
valid (check if the complement is satisfiable), and, if it's not,
produce an example of a sequence that satisfies p but not q.

I would appreciate references to published work.

Thanks,

Larry

---

Larry M. Augustin			ERL 414, M/C 4055
lma@dayton.stanford.edu			Computer Systems Lab
+1 415.723.9285 (voice)			Stanford University
+1 415.725.7398 (fax)			Stanford, CA 94305

Newsgroups: sci.logic
From: sbloch@silver.cs.umanitoba.ca (Stephen Bloch)
Subject: Re: enigma
Organization: Computer Science, University of Manitoba, Winnipeg, Canada
Distribution: na
Date: Tue, 8 Sep 1992 22:13:39 GMT

bouchard@ireq.hydro.qc.ca (Marco Bouchard ETUDIANT sept-dec 92) writes:
>You have 10 vending machines to fill out with chocolate bars. In fact,
>after finishing to put the chocolate, you remember that you had 9 boxes
>of chocolate bars of 100g. and one box of bars of 90g and you gotta know
>in which machine you put those of 90g....
>You can weigh as [many]
>bars as you want, but you can take one measure.    

mab@wdl39.wdl.loral.com (Mark A Biggar) replies:
>Take 1 bar from machine #1, 2 bars from machine #2, ... and 10 bars from
>machine #10.  Weight the whole set of bars.  The expected weight is 5500g.
>But some of the bars weight only 90g, so the actual weight will be some
>number of 10g increments less then 5500g, that number is the number of the 
>machine with the 90g bars.

Of course, this approach can be generalized to handle the case in
which you're not sure how many of the boxes were underweight: take 1
bar from machine #1, 2 from #2, 4 from #3, 8 from #4, etc.  Only
problem is, one of the vending machines has to be capable of holding
1024 chocolate bars, and your scale has to be able to handle over 200 kg
of chocolate.  And then there's the question of what to DO with over
200 kg of chocolate... :-)

-- 
					Stephen Bloch
				sbloch@silver.cs.umanitoba.ca
Newsgroups: sci.logic
From: holmes@opal.idbsu.edu (Randall Holmes)
Subject: Re: Set Theory and Theology
Organization: Boise State University Math Dept.
Distribution: sci.logic sci.philosophy.meta
Date: Thu, 10 Sep 1992 17:44:35 GMT

In article <BuBCCp.6wJ@unx.sas.com> sasghm@theseus.unx.sas.com (Gary Merrill) writes:
>
>In article <1992Sep8.204819.316@guinness.idbsu.edu>, holmes@opal.idbsu.edu (Randall Holmes) writes:
>|> 
>|> 
>|> Please note that the existence of the set of all natural numbers is
>                                         ^^^
>|> sanctioned by one of the Fathers of the Church.  Note the use of
>
>This is not obvious.  I am suspicious of the translation, you clever
>promulgator of Platonism.
>
>|> Every number is defined by its own unique character, so that no number
>|> is equal to any other.  They are all unequal to one another and
>|> different, and the individual numbers are finite, but as a class they
>                                                              ^^^^^
>Class?  Do you have the Latin here?
>
>|> Never let us doubt, then, that every number is known to him 'whose
>|> understanding cannot be numbered'.  Although the infinite series of
>
>Of course, this doesn't require there to be a set of same.
>-- 
>Gary H. Merrill  [Principal Systems Developer, C Compiler Development]
>SAS Institute Inc. / SAS Campus Dr. / Cary, NC  27513 / (919) 677-8000
>sasghm@theseus.unx.sas.com ... !mcnc!sas!sasghm

St. Augustine does not refer directly to the existence of the set of
natural numbers, but refer to the last paragraph of the quote, which
you did not include, where he points out that the infinity of natural
numbers is "finite" to God.  This certainly seems to support the
existence of "omega".
-- 
The opinions expressed		|     --Sincerely,
above are not the "official"	|     M. Randall Holmes
opinions of any person		|     Math. Dept., Boise State Univ.
or institution.			|     holmes@opal.idbsu.edu
Newsgroups: sci.logic
From: holmes@opal.idbsu.edu (Randall Holmes)
Subject: Re: Set of all sets
Organization: Boise State University Math Dept.
Date: Tue, 8 Sep 1992 16:50:51 GMT

In article <1992Sep7.225943.23043@infodev.cam.ac.uk> gjm11@cus.cam.ac.uk (G.J. McCaughan) writes:
>In article <1992Sep7.062552.21596@guinness.idbsu.edu> holmes@opal.idbsu.edu (Randall Holmes) writes:
>
>> A brief remark:  I do know that the consistency of ZFC is itself open
>> to doubt.  I agree that one can equally well start working in NF with
>> faith in one's heart as we already can in ZFC.  But to start working 
>> in NF, we must give up the Axiom of Choice; this is the real problem
>> from my standpoint.  I have other reasons for doubting the naturalness
>> of NF (but not of NFU) which are not ready for publication.
>
>Hmm. I don't know much about what is and isn't consistent with NF.
>Is Dependent Choice consistent with NF? That would satisfy many of us,
>perhaps including some who don't like the Axiom of Choice in all its
>-- 

The strongest version of Dependent Choice is false in NF, but
there is a weaker version adequate for practical purposes which
appears to be OK.  The problem is that we do not have good techniques
for proving relative consistency results for NF; we do not even know
if denumerable choice or "the real numbers can be well-ordered" are
consistent to adjoin to NF, although we do not see any reason to doubt
this.

-- 
The opinions expressed		|     --Sincerely,
above are not the "official"	|     M. Randall Holmes
opinions of any person		|     Math. Dept., Boise State Univ.
or institution.			|     holmes@opal.idbsu.edu
Newsgroups: sci.logic
From: torkel@sics.se (Torkel Franzen)
Subject: Re: How does one formalize "small" mathematical theories?
Organization: Swedish Institute of Computer Science, Kista
Date: Sun, 13 Sep 1992 21:26:25 GMT

In article <1903t2INNanu@cs.utexas.edu> turpin@cs.utexas.edu (Russell Turpin)
 writes:

   >For some theories, there are classical axiomatizations that stand
   >apart from set theory, e.g., arithmetic, real algebra, and plane
   >geometry.  Curiously, these all have intuitive axiomatizations
   >that do not rely on sets, and at least in the case of arithmetic
   >and plane geometry, axioms that were stated before set theory was
   >developed.  But the "natural" axioms for groups seem to rely on
   >sets: "a group is a *set* with a binary operator + such that ..."

  The concept of a group involves the notion of set, but the
elementary group axioms don't rely on sets any more than the axioms of
any other first order theory. If you want to talk about all models of
the axioms of elementary arithmetic, or about all real-closed fields
you will again speak of sets. In ordinary mathematics, one is very
much concerned with general models of the elementary group axioms,
which were introduced precisely to describe a structure common to many
mathematical objects, but not with general models of the axioms of
elementary arithmetic.

  Most group theory of course cannot be formulated within the elementary
theory of groups, for the reason indicated above. If you want a theory
weaker than ZFC within which e.g. the study of finite groups can be carried
out, such theories have been formulated, and somebody more knowledgeable
will be able to give a suitable reference.

  However, I wish to take issue with your statement that the classical
axiomatizations of arithmetic, real algebra, or elementary geometry do
not rely on sets. In each case the intuitive axiomatization does rely on
some notion of set (of natural numbers, of real numbers, of points) -
namely in the induction axiom or some continuity axiom (such as the
completeness axiom for ordered fields). The corresponding first order
theories are another matter. In the case of arithmetic, the first
order theory is as we know incomplete, in the case of the real numbers,
it turns out to be complete. But in both cases, the classical and
intuitive axiomatization is the second order one.


Newsgroups: sci.logic
From: DUENTSCH@dosuni1.rz.uni-osnabrueck.de
Subject: Re: Set of all sets + correcting MZ's syntax
Organization: University of Osnabrueck, FRG
Date: Tue, 8 Sep 1992 06:54:58 GMT

In article <4134@seti.UUCP>
ziane@nuri.inria.fr (ziane mikal -) writes:
 
>The question is now, whether or not alternative axiomatizations
>have been proposed that are consistent with the existence of the
>set of all sets ?
 
In the 1920's Paul Finsler proposed a system of set theory in which
a set of all sets is allowed. His system is not formal (in Hilbert's
sense); the discussion of his system within the mathematical community
was rather emotional and not free from personal animosities. In
his system, Finsler showed incompleteness before Goedel.
As far as I know, a serious and in depth study of his Finsler's set
theory has yet to be done.
 
Ivo Duentsch
Rechenzentrum
Universitaet Osnabrueck
duentsch@dosuni1.rz.uni-osnabrueck.de
Newsgroups: sci.logic
From: klaus@hal.nta.no (Klaus Gaarder FNI)
Subject: Re: infinite state automaton
Organization: Norwegian Telecom Research
Date: Tue, 8 Sep 92 08:14:01 GMT

In article <UedH4ge00WB80CdOB6@andrew.cmu.edu>, Leslie Burkholder <lb0q+@andrew.cmu.edu> writes:
|> Suppose we allow an automaton to have an infinite rather than a finite
|> number of states. Is that (equivalent to) a Turing machine? References,
|> please.
|> Thanks,
|> Leslie Burkholder

A Turing machine can be considered to have an infinite number of states if you 
define each state by including the contents of the tape in addition to each of
the finite number of states, thus giving a countable number of states.

This is probably best seen by considering the algebraic way of defining both
finite state machines and Turing machines.

References:

Good old Marvin Minsky: Finite and Infinite Machines, Prentice Hall
Has an example of an infinite state machine for parenthesis checking

Michael Arbib and Ernest Manes: Arrows, Structures And Functors, Academic Press
Chapter 6, sect. 6.3, contains the relevant definition, making the *finite* case
a special case. That is, you could even imagine an automaton with an uncountable
number of states, say one for each real number.........eat that!

Sincerely
Klaus Gaarder@Norwegian Telecom Research.

-- 
    __o   
  _`\<,_  
 (*)/ (*) Claudio Caputti
+++++++++++++++++++++++++++++++++++++++^++++++++++++++++++++++++++++++++++++++
Free will - the result of chaotic amplification of quantum events in the brain.
------------------------------------------------------------------------------