HDTenEightyP/NetNews huggingface dataset:
From: jedwards@ms.uky.edu (Jonathan Edwards)
Subject: Re: Q: DigiCash & electronic money
Date: Wed, 15 Apr 1992 22:04:25 GMT
Organization: University Of Kentucky, Dept. of Math Sciences
X-Bytes: 

bs891@cleveland.Freenet.Edu (Robert Anderson) writes:


>Apparently David Chaum is one of the main people involved.
>I found a paper by him and 2 others in the Crypto 88
>proceedings which describes an electronic cash system that
>sounds like what DigiCash is doing.

>You go to the "bank", in this case DigiCash, and withdraw
>money by offering a "blinded" random number for them to sign.
>You can then unblind the number so that even the bank can't
>recognize it, but you can still spend it by showing the
>store the bank's signature.  The store then sends the number
>back to the bank and gets paid.

>The really clever feature is that the bank can't recognize
>the numbers as they come in from the stores in terms of who
>withdrew them.  That is, it can't unless you try to cheat and
>spend the same number twice.  Spending the money involves
>going through a little protocol with the store owner, and
>some randomness in the protocol ensures that if you do it
>twice, you'll reveal enough information that the bank can
>figure out who you are.  Then they can sue you, or at least
>shut your account down.

This protocol was not described in Chaum's 1985 paper and I have
been trying to figure out how he intended to prevent such counter-
feiting.  Can you please post or e-mail a reference to the paper
wherein it is discussed?
From: smith@sctc.com (Rick Smith)
Newsgroups: sci.crypt
Subject: Re: The idea of a flood cryptosystem
Date: 10 Apr 92 19:52:48 GMT
Organization: SCTC

brnstnd@nyu.edu (Dan Bernstein) writes:

>In tomorrow's high-speed networks it will be possible to overwhelm a
>typical listener's expected ability to record a lengthy message. 

Shouldn't we expect tomorrow's high speed networks to arrive at
about the same time as tomorrow's multi-gigabit removable floppies
and streaming tape, etc?

Rick.
smith@sctc.com       arden hills, minnesota
From: richard@aiai.ed.ac.uk (Richard Tobin)
Newsgroups: sci.crypt
Subject: Re: Random-dot stereograms
Date: 8 Apr 92 17:00:48 GMT
Organization: AIAI, University of Edinburgh, Scotland

In article <j98fm2s@sgi.sgi.com> rpw3@rigden.wpd.sgi.com (Rob Warnock) writes:
>The "key" image *can* be pre-computed, and indeed can be
>used as the "key" for several coded images. [Hey, this is neat!]

Using the same key twice has the same problem as using a one-time pad
twice.  In fact, I suspect (though I don't have any here to try with)
that if you used two encoded images from the same key as a pair, you'd
see something much like the two plain-images superimposed.

-- Richard
-- 
Richard Tobin,
AI Applications Institute,                                R.Tobin@ed.ac.uk
Edinburgh University.
Newsgroups: sci.crypt
From: wayner@cs.cornell.edu (Peter Wayner)
Subject: Re: Random-dot stereograms
Organization: Cornell Univ. CS Dept, Ithaca NY 14853
Date: Wed, 8 Apr 1992 14:56:30 GMT

rpw3@rigden.wpd.sgi.com (Rob Warnock) writes:

>+---------------
>| richard@aiai.ed.ac.uk (Richard Tobin) writes:
>| > The recipient would be provided in advance with one half of the
>| > stereogram, and the other half would be constructed when needed.  
>+---------------

>Cute! I like it!

Here's another trick that's been hanging around the fence:

Encode the information in the least significant bits of either
photographs or musical data. In fact you can use compression algorithms
like JPEG to determine what the "significant" bits are. Just compress
and see which areas of the photo are mapped into the same value. The
bits that used to distinguish the very subtle color shades in this region 
probably aren't that valuable. This way you can let all the compression
guys worry about psycho-physical thresholds. 

There is sooo much noise in the world just waiting to hold the secret
messages of the world. 

-Peter

-- 
Peter Wayner   Department of Computer Science Cornell Univ. Ithaca, NY 14850
EMail:wayner@cs.cornell.edu    Office: 607-255-9202 or 255-1008
Home: 116 Oak Ave, Ithaca, NY 14850  Phone: 607-277-6678
From: mrr@scss3.cl.msu.edu (Mark Riordan)
Newsgroups: sci.crypt
Subject: Re: Public Domain RSAREF-based PEM Projects?
Date: 16 Apr 92 20:43:08 GMT
Organization: Michigan State University

mather@sees.bangor.ac.uk (Paul Mather) writes:
: 
: I'm a little confused.  I thought RSAREF had a pretty strict license
: agreement surrounding it and, importantly, could not be exported
: outside the USA.  As such, non-USAn's such as myself cannot use it.

Right about exportability.  Of course, if someone were to write a PEM
program that relied upon RSAREF, the source code to that program
would be exportable.  But when you compiled & linked it, you'd 
find a lot of unsatisfied external references.  Sorry--I sympathize
with your plight, but can't see a way of addressing it from where I
sit. 

Rumor has it that the licensing restrictions on RSAREF will
be relaxed in the not-too-distant future.  This will make it
more practical to distribute apps based on RSAREF.
 
: By the way, what is the current status of RPEM?

I am no longer distributing it.  

Mark Riordan   riordanmr@clvax1.cl.msu.edu
From: eab@uh.msc.edu (Edward Bertsch)
Newsgroups: sci.crypt
Subject: Using a PC & modem as a secure 'voice' telephone
Date: 16 Apr 92 03:06:23 GMT
Article-I.D.: uc.1992Apr16.030623.29152
Organization: Minnesota Supercomputer Center


There was some talk recently about secure telephones, and an 'encrypting'
cordless telephone made by motorola (which wasn't very secure at all).
The talk about the professional 'secure' telephones (MIL-std devices
that cost big bucks) made it sound like the basic system was

 voice -> mic -> A/D converter -> encrypt circuit or algorithm -> modem ->
 telephone line -> modem -> decrypt circuit or algorithm -> D/A converter ->
 speaker

Certainly this can be done with an IBM PC, Macintosh, Amiga, Sparcstation,
or other computer that many already have.

So, my question is, does anyone know of a software/soft&hardware solution
for secure voice communication over telephone lines?

By secure, I guess I mean DES or safer encryption.


--

Edward A. Bertsch (eab@msc.edu)   Minnesota Supercomputer Center, Inc.
Operations/User Services          1200 Washington Avenue South
(612) 626-1571 work               Minneapolis, Minnesota  55415
(612) 645-0168 voice mail

	"Read _MY_ lips: I won't be voting for Bush in 1992"
Newsgroups: sci.crypt
From: sean@ms.uky.edu (Sean Casey)
Subject: Re: Random-dot stereograms
Date: Tue, 7 Apr 1992 22:12:49 GMT
Organization: University Of Kentucky, Dept. of Math Sciences
X-Bytes: 

I find this interesting. If you represent text photographically, i.e.
your ciphertext is an image, does that make attacks harder? It seems
on first thought that traditional techniques would not work, and image
recognition algorithms would need to be used.

Very interesting...

Sean
-- 
                  |``Wind, waves, etc. are breakdowns in the face of the
Sean Casey        | commitment to getting from here to there. But they are the
sean@s.ms.uky.edu | conditions for sailing -- not something to be gotten rid
U of KY, Lexington| of, but something to be danced with.''
Newsgroups: sci.crypt
From: ab@dist.dist.unige.it (Alessandro Berni)
Newsgroups: sci.crypt
Subject: Re: Q: DigiCash & electronic money
Date: 16 Apr 92 14:32:07 GMT
Reply-To: ab@dist.dist.unige.it (Alessandro Berni)
Organization: DIST - Universita` di Genova

In article <1667@alcbel.be>, fjoh@alcbel.be (Ferry Johann) writes:
|> I think the company you refer to is called CWI (Centre for Mathematics and
|> Information Science). I only know they are in the Kruislaan at Amsterdam or
|> Amstelveen. You should contact them yourself to get more information. The guy
|> who knows more about is is called David Chaumbers (I thought).
|> 
|> Ferry Johann
|> Alcatel Bell Research Centre
|> Francis Wellesplein 1
I hope you will find this information useful:

address: Centrum voor Wiskunde en Informatica
address: Kruislaan 413
address: NL-1098 SJ Amsterdam
address: Netherlands

-- 
Alessandro Berni			ab@italy.EU.net
D.I.S.T.			    	 ...!mcsun!i2unix!ab
Universita` di Genova
Via Opera Pia, 11a 			+39 10 3532747   (voice)
I-16145 Genova, Italy	 		+39 10 3532948	 (fax)
Italy					272399 DIE GE I  (telex)
Newsgroups: sci.crypt
From: pciszek@isis.cs.du.edu (Paul Ciszek)
Subject: Question inspired by _The Mathematical Gardner_
Summary: how secure is y = (s*x) mod r  ?
Keywords: modulo arithmetic, Backpack codes, factoring
Organization: University of Denver, Dept. of Math & Comp. Sci.
Date: Tue, 14 Apr 92 05:57:24 GMT

I was reading the article "Error Correcting Codes and Cryptography" in
_The Mathematical Gardner_ (A wonderful book, by the way) and noticed
something interesting in a discussion of the early Backpack codes.  (Yes,
I know the Backpack code has been broken, but bear with me)  This was
probably a simplified version of what was really going on, but the
article described the following method for creating the scrambled backpack
numbers for use in the encryption key:  Take the first n powers of 2
expressed in n-bit format, prefix and suffix them with a few random
digits (plus a column of zeros to protect the powers-of-2 from carries)
multiply the entire number by s, modulus r.  It seemed that the encrypters
first concern is that someone will solve the Backpack problem for the 
scrambled integers, not that someone will figure out r and s and thus
know how to decrypt.  In a later article by Martin Gardner himself, he
mentions that the Backpack problem had been solved in polynomial time
for most codes, so apparently this was the most fruitful way to attack
this code.  Now, it seems to me that the codebreaker knows a fair amount
of the "text" of those scrambled numbers (that they are the powers of
2 with a little noise on each end) and has n examples encrypted with
the same r,s key.  Is there no means of finding r and s?  Is y = (s*x) mod r
considered a good "conventional" cryptosystem, safe against plaintext
attack?  Or am I missing something?

--
Paul Ciszek, pciszek@nyx.cs.du.edu | Saddam Hussein still has a job; do you?
Newsgroups: sci.crypt
From: wayner@cs.cornell.edu (Peter Wayner)
Subject: Depth of DES S-Boxes in "Gates"
Organization: Cornell Univ. CS Dept, Ithaca NY 14853
Date: Tue, 14 Apr 1992 13:09:06 GMT


I remember a discussion not too long ago about the number of logic
gates necessary to simulate the bits of the DES S-box. Someone
observed that the DES S-boxes are more complex than random boxes. In
this case the measure of complexity is the number of logic gates that
it takes to simulate the result.  Can anyone point me to a reference
on this subject?


Thanks,

Peter Wayner
(wayner@cs.cornell.edu)

-- 
Peter Wayner   Department of Computer Science Cornell Univ. Ithaca, NY 14850
EMail:wayner@cs.cornell.edu    Office: 607-255-9202 or 255-1008
Home: 116 Oak Ave, Ithaca, NY 14850  Phone: 607-277-6678
From: bs891@cleveland.Freenet.Edu (Robert Anderson)
Subject: Q: DigiCash & electronic money
Organization: Case Western Reserve University, Cleveland, Ohio, (USA)
Date: Tue, 14 Apr 92 04:22:14 GMT


I saw a copy of the online newsletter of the
Electronic Frontier Foundation, and they had a
mention of a talk at the Computers, Freedom and Privacy
conference by Eric Hughes of DigiCash.

Apparently DigiCash is hoping to set up a system of
"electronic money".  You could order, say, documents over
the Internet and pay for it with this "money".  Transactions
would be confidential and anonymous.  It would be like
cash in that way.

It relies on cryptography for its security and anonymity.
I've heard that the company is based on the Netherlands and
has some top cryptography people associated with it.

Does anyone have more information on DigiCash, and the
specifics of their money system?

Bob Anderson
From: spencer@rise.Princeton.EDU (S. Spencer Sun)
Newsgroups: sci.crypt
Subject: Re: Source for _real_ random numbers
Date: 16 Apr 92 18:28:28 GMT
Distribution: na
Organization: Princeton Univ. Class of '94
Originator: news@ernie.Princeton.EDU

In _Clear and Present Danger_ someone sends a set of coordinates to
someone else by giving him the dictionary words (what are they called?
index words?  I forget, this goes back to second grade) on the pages
whose numbers are the appropriate coordinates...

I suppose this relies on others not being able to figure out what
dictionary you're using...
----------
Spencer Sun - Princeton Univ. Class of '94 - Dept. of Computer Science
Clockwork Orange (Princeton Ultimate) (when I bother to show up for practice)
Playing bridge is like having sex.  You don't need a partner if you
have a good hand.
From: anthonyb@cs.uq.oz.au (Anthony Bloesch)
Newsgroups: sci.logic
Subject: Publicly available logic problem sets
Date: 8 Apr 92 22:49:01 GMT
Reply-To: anthonyb@cs.uq.oz.au

I suppose this is a FAQ so I'll tender my apologies first.  But are
there any ftp'able logic problem sets on the net (preferably in infix
notation).  I  am interested in problems in any logic (Classical,
paraconsistent, relevant, etc); theorems as well as nontheorems.
The larger the problem set the better as I will be using them to test a
general purpose theorem prover I have written.  While I can, and have,
generated random theorems and nontheorems they are often uninteresting
(e.g. Nontheorem -> Simple Theorem).

Please email me and I will summarize the responses in a later posting.
I am already aware of the problem sets that come with KRIPKE and Otter as
well as the morgan problem set of anagram.mcs.anl.gov:/pub/ATP_problems
fame.

                                   Anthony
From: jack@dcs.glasgow.ac.uk (Jack Campin)
Newsgroups: sci.logic
Subject: modal set theory
Date: 13 Apr 92 19:24:51 GMT
Organization: Glasgow University Computing Science Dept.

It seems surprising that nobody here has yet mentioned Aldo Bressan's work.
He's been investigating modal set theories for years.  His book "A General
Interpreted Modal Calculus" (Yale UP, around 1973) describes a modal simple
type theory originally intended to analyze the modal issues arising in
Painleve's formulation of axiomatic classical mechanics; he later extended
this to a modal Morse-Kelley set theory and did some papers on
probabilistic set theories.  All these theories are, of course, intended to
describe empirical domains of discourse.

Daniel Gallin's thesis (published as a book around 1976, I forget where)
showed that Bressan's GIMC theory is in some sense inter-translatable with
Montague's Intensional Logic.  I don't know of any Montague-like analogue
of Bressan's later stuff.

Most of Bressan's papers are in the Rendiconti of the University of Padova
(his home turf).

-- 
--  Jack Campin    room G092, Computing Science Department, Glasgow University,
17 Lilybank Gardens, Glasgow G12 8RZ, Scotland   TEL: 041 339 8855 x6854 (work)
INTERNET: jack@dcs.glasgow.ac.uk or via nsfnet-relay.ac.uk    FAX: 041 330 4913
BANG!net: via mcsun and uknet     BITNET: via UKACRL    UUCP: jack@glasgow.uucp
From: suchenek@nic.csu.net
Newsgroups: sci.logic
Subject: Re: Set theory and modal logic
Date: 16 Apr 92 12:38:05 PDT
Organization: Information Resources and Technology

In article <1992Apr14.085858.11068@husc3.harvard.edu>, zeleny@zariski.harvard.edu (Mikhail Zeleny) writes:
[...]
> 
> MS:
>>How, without the necessitation rule (and scheme K), can you get 
>>
>>     p \supset \box (\box (p \supset q) \supset (\box p \supset \box q))
>>
>>(which is a theorem of S4 and S5), without proving too much, e.g.
>>
>>      p \supset \box p
>>
>>(which is not a theorem of S4 and S5), where p is a propositional variable?
>
[MZ:] 
> Easy.  We select a subsystem generated by all axioms of S5 (or S4).  Do you
> doubt that these axioms could be obtained from A \equiv \box A ?  In fact,
> on the purely syntactic level of abstraction we are considering, we needn't
> even concern ourselves with RNec and other such matters.


Not really. Using A \equiv \box A you prove too much, e.g. the unwanted
sentence p \supseteq \box p, where p is a propositional variable.

Greetings, 

Marek A. Suchenek
Computer Science
Cal State Dominguez Hills
1000 E Victoria St
Carson CA 90747

Newsgroups: sci.logic
From: BR.MJC@forsythe.stanford.edu (Michael Carroll)
Subject: Re: Set theory and modal logic
Organization: Stanford University, California, USA
Distribution: usa
Date: Fri, 10 Apr 1992 23:46:44 GMT

In article <1992Apr10.013706.28964@morrow.stanford.edu>,
BR.MJC@forsythe.stanford.edu (Michael Carroll) writes:
> . . . . . And, in general, the interior and closure of x will be distinct
>from each other and from x itself.

Oops. This has not been shown. And the point of Loader's original
comment, which someone was kind enough to explicate for me, is
precisely that merely adding logical axioms for modal operators is
not enough to guarantee this.
--
Michael Carroll
Research Libraries Group
Newsgroups: sci.logic
From: cxm7@po.CWRU.Edu (Colin Mclarty)
Subject: Re: Set theory and modal logic
Reply-To: cxm7@po.CWRU.Edu (Colin Mclarty)
Organization: Case Western Reserve University, Cleveland, OH (USA)
Date: Wed, 8 Apr 92 16:10:29 GMT


In a previous article, logic@gacvx2.gac.edu () says:

>In article <1992Apr7.124948.5325@vax.oxford.ac.uk>, loader@vax.oxford.ac.uk (R Loader) writes:
>
>> S4 and S5 (and most other common modal logics), are subsystems of classical
>> (non-modal) logic extended with the axiom: A iff \box A.
>
>Other stuff deleted....
>
>> Ralph Loader,
>> Mathematical Institute, Oxford.
>
>S4 and S5 are supersystems, not subsystems, of classical logic..  Neither
>contain the axiom "A iff \box A", both contain the axiom "if \box A then A".
>
>Al Hart
>

I made the same mistake at first.  You have to read Loader's post more
carefully.

Colin McLarty
From: zeleny@zariski.harvard.edu (Mikhail Zeleny)
Newsgroups: sci.logic
Subject: Re: Set theory and modal logic
Date: 14 Apr 92 12:58:56 GMT
Organization: Dept. of Math, Harvard Univ.

In article <1992Apr13.114824.1745@nic.csu.net> 
suchenek@nic.csu.net writes:

>In article <1992Apr12.193331.11012@husc3.harvard.edu>,
>zeleny@zariski.harvard.edu (Mikhail Zeleny) writes: 

MZ:
>> Observe that Ralph says that S4 and S5 are *subsystems* of classical logic
>> extended with the axiom: A iff \box A. In that, he is absolutely correct: a
>> subsystem needn't contain the axiom in question, but only a deductively
>> closed proper subset of its consequences, e.g. those generated by \box A
>> \supset A in the presence of classical laws.  However, I am not sure
>> whether he could do without an additional rule of inference, viz. the Rule
>> of Necessitation:
>> 
>> 		A
>> 	       ___
>> 
>> 	      \box A
>> 
>> which prima facie seems to be required for adequately characterizing S4 and
>> S5, even if all of their theorems can probably be obtained by the above
>> process.

MS:
>How, without the necessitation rule (and scheme K), can you get 
>
>     p \supset \box (\box (p \supset q) \supset (\box p \supset \box q))
>
>(which is a theorem of S4 and S5), without proving too much, e.g.
>
>      p \supset \box p
>
>(which is not a theorem of S4 and S5), where p is a propositional variable?

Easy.  We select a subsystem generated by all axioms of S5 (or S4).  Do you
doubt that these axioms could be obtained from A \equiv \box A ?  In fact,
on the purely syntactic level of abstraction we are considering, we needn't
even concern ourselves with RNec and other such matters.

>Greetings,
>
>Marek Suchenek

regards,
mz

`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'
: Qu'est-ce qui est bien?  Qu'est-ce qui est laid?         Harvard   :
: Qu'est-ce qui est grand, fort, faible...                 doesn't   :
: Connais pas! Connais pas!                                 think    :
:                                                             so     :
: Mikhail Zeleny                                                     :
: 872 Massachusetts Ave., Apt. 707                                   :
: Cambridge, Massachusetts 02139           (617) 661-8151            :
: email zeleny@zariski.harvard.edu or zeleny@HUMA1.BITNET            :
:                                                                    :
'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`
From: maj@waikato.ac.nz
Newsgroups: sci.logic
Subject: Mystical reflections
Date: 7 Apr 92 16:05:53 +1200
Organization: University of Waikato, Hamilton, New Zealand

I'm enjoying reading sci.logic after a break of nearly 20 years from
thinking about such matters. [ These days I'm a statistician, an area
that I also enjoy and which shares with logic the agreeable tradition
of public argument over foundational matters. ] I thought that some
of you might be intrigued by a mystical interpretation of the
principle of reflection. I'm usually of a sceptical turn of mind, but
sometimes I go into a mystical mode to break the monotony.

I vaguely remember the principle of reflection as asserting that a
sentence of set theory true in the universe can also be satisfied in 
a proper submodel of the universe. This means that any attempt to
describe the universe by such a sentence fails.

In Ursula Le Guin's book 'City of Illusion' the main character regains 
his memory when he reads the saying

     The way that can be gone
     is not the eternal Way
				 
     The name that can be named
     is not the eternal Name

the first couplets from the 'Tao te ching' by Lao-tzu, the main Taoist 
scripture.


The parallel between this Taoist saying and the reflection principle
is rather striking. Do both express something deep about limitations
in how we can understand the universe that we inhabit ?

BTW, I set up my .sig before the recent discussion on Lewis Carroll.
-- 
Murray A. Jorgensen                       internet: maj@waikato.ac.nz
Department of Mathematics and Statistics     phone: +64-7 856 2889
University of Waikato                          fax: +64-7 838 4155
Hamilton, New Zealand      [Venue for IBC 92, 7-11 December, 1992]
______________________________________________________________________________
'Tis the song of the Jubjub! the proof is complete,
if only I've stated it thrice.'