HDTenEightyP/NetNews huggingface dataset:
From: ritley@uimrl7.mrl.uiuc.edu
Newsgroups: sci.materials
Subject: Info regarding ultrasonic cleaning
Date: 6 Oct 92 13:58:09 GMT
Article-I.D.: news.BvpDGz.9y6
Reply-To: ritley@uiucmrl.bitnet ()
Organization: Materials Research Lab


I understand that ultrasonic cleaning is an interesting process,
involving cavitation, brief temperature fluctuations, etc.

Might anyone know off-hand a good reference which describes
this process?
From: zaval@athena.mit.edu (Antonis)
Newsgroups: sci.materials
Subject: IM6 or IM600 fiber
Date: 28 Sep 92 03:36:51 GMT
Organization: Massachusetts Institute of Technology

I was looking for a supplier of IM600 carbon fibers
and I found one for IM6. Does anybody know if they are different ?

antonis zavaliangos

ps. Iwould appreciate if you could e-mail any info to 
    zaval@duvm.ocs.drexel.edu
Newsgroups: sci.materials
Subject: Re: Optical pyrometry for MBE
From: ianbjor@argon.gas.uug.arizona.edu (Ian D. Bjorhovde)
Date: 28 Sep 92 20:00:03 GMT
Organization: University of Arizona, Tucson, AZ
Keywords: Pyrometry, MBE, III-Vs, Temperature

In article <1992Sep28.071622.3040@trl.oz.au> jdell@trl.OZ.AU (John Dell - Photonics) writes:

>Anyway, the problem (at last) is that we need to measure lowish temperatures
>now (of the order of 300-500 C) and we would like some recommendations of how
>to do this using optical pyrometry.  What have been peoples' experiences, how
>do you calibrate the system, what products are available, how accurate
>are they, how precise are they, do you look at the block or the semiconductor,
>have you had to worry about the window (ie do you need a sapphire window
>or will a standard window do and simply change the effective emissivity), 
>do you need to heat the window to prevent condensation of As, how do you
>limit the field of view .....? 

Last spring I worked with an Optical Pyrometer attempting to measure
(accurately) the maximum temperatures on Si using an Nd:YAG (1.06um)
beam, with very little success.  Although we were looking for
temperatures near 1600K, we still learned quite a bit about optical
pyrometry.

We found the biggest consideration to be how much area on the sample
that you need to see.  We needed a resolution such that the window that
the pyrometer saw was about 300um wide - which is very difficult to
attain.  The problems in viewing an area this small come from the fact
that the lens must be _very_ close to the sample.  Since we were trying
to look at the surface temperature, our situation was  a little
different than yours because we needed to look at the sample head on.

Our pyrometer was made by Inframetrics (I don't remember the model
number offhand) but we found it to be very accurate in other (larger
scale) situations.  Simply looking into a tube furnace revealed only a
2-3 degree difference between the pyrometer and the furnace controller;
Calibration was performed by Inframetrics.

Please send me email and I can dig up some old manuals and notes to give
you more information.


Ian D. Bjorhovde
ianbjor@gas.uug.arizona.edu  -or-  ianbjor@convx1.ccit.arizona.edu
Department of Materials Science & Engineering
University of Arizona, Tucson AZ
Newsgroups: sci.materials
From: robinsmm@ucsu.Colorado.EDU (ROBINSON MARYBETH)
Subject: Re: Uses of Be
Organization: University of Colorado, Boulder
Date: Mon, 5 Oct 1992 15:20:19 GMT

In article <1992Oct2.113921.2739@mtroyal.ab.ca> dhayward@mtroyal.ab.ca writes:
>For years I have been interested in the present and future uses of
>Berrylium. Due to it's many spectacular properties it should be more
>common than it is. any info?


I recently read in Velo News that there is some consideration in using
Be for bicycle frames.  Only problem ----- $$$$$$$$.  But I imagine
that if there are thousands f people in the world willing to spend
thousands on Ti frames, why nopt Be?

mb

.

-- 
MaryBeth (MB) Robinson    		robinsmm@ucsu.Colorado.edu
Department of Chemistry
University of Colorado
From: jake@nucst6.neep.wisc.edu (james blanchard)
Newsgroups: sci.materials
Subject: Re: Uses of Be
Date: 5 Oct 92 16:35:23 GMT
Article-I.D.: nucst6.JAKE.92Oct5093523
	<hwbp3dc@dixie.com>
Organization: /usr1/jake/.organization
In-reply-to: jgd@dixie.com's message of 3 Oct 92 19:28:43 GMT

In article <hwbp3dc@dixie.com> jgd@dixie.com (John De Armond) writes:

> >What are the spectacular properties?

> Very light weight, very strong, transparent to X-rays down to very low
> energies, good neutron moderator, excellent heat conductor, as an oxide, 
> a very good electrical insulator while being a very good thermal 
> conductor.  Be is the lightest metal with any structural use.

     Be is also a good neutron multiplier, so the fusion community
tends to use a lot of it in their conceptual reactor designs, in order
to maximize the number of available neutrons and the resultant amount
of tritium produced by reactions with lithium.
     Lately, some of the experimental fusion devices are using it as a
coating on some of the components that interact with the plasma.  This
assures low molecular weight plasma impurities and thus reduced
radiation from the plasma.  Another positive feature of Be in this
context is its apparent gettering properties, which tend to keep the
plasma clean.  I believe the JET reactor in England uses Be coatings. 
     Also, the aerospace industries have put quite a bit of effort
into investigating the use of beryllium alloys, becaue they're so
light.  The major drawback seems to be its lack of ductility.  I could
probably dig up some references to this work if anyone was interested.
--

   jake blanchard
   university of wisconsin - madison
   nuclear engineering and engineering physics
   (608) 263-0391
   blanchar@engr.wisc.edu
   jake@nucst6.neep.wisc.edu
From: aoutzour@slate.mines.colorado.edu (OUTZOURHIT ABDELKADE)
Newsgroups: sci.materials
Subject: High temperature electrical insulation
Keywords: Insulation, Platinum wire, thermal conductivity
Date: 28 Sep 92 00:31:08 GMT
Followup-To: none
Distribution: USA
Organization: Colorado School of Mines

I am trying to modify a hot-wire cell for thermal conductivity 
measurement so that electricall conducting materials can be studied. The
materials (powders, fluids,..) surround a thin platinum wire. This technique
is widely used to measure the thermal properties of insulating materials.
The problem is that I am using a 25.4 microns bare Pt wire. The 
resistance of the Pt wire (from which the temperature is found) 
will be affected by the electrically conducting material depending on
 the conductivity of the later. I am looking for a high temperature (above 
500 C)  electrically insulating paint that I can use (either by spraying
 or brushing) to insulate the wire  from the surrounding medium. Any 
suggestions are appreciated.

----------------------------------------------------------
A. Outzourhit

e-mail: aoutzour@slate.mines.colorado.edu
Tel: (303) 273-3832 
Newsgroups: sci.materials
From: lewis@aera8700.mitre.org (Keith Lewis)
Subject: Re: PGP weak on long messages (was: Re: pgp2.0 ... key length?)
Organization: The MITRE Corporation
    <1992Oct04.084900.19815@spillman.uucp>
Date: Tue, 6 Oct 1992 20:07:28 GMT

In article <1992Oct04.084900.19815@spillman.uucp>, tye@spillman.uucp (E. Tye McQueen) writes:
>lewis@aera8700.mitre.org (Keith Lewis) writes:
>)PGP is essentially RSA performed on a bitmask which is used repeatedly on
>)a single message.
>
>Doesn't reusing the (encrypted) bit mask make long messages fairly
>easy to crack if you have ideas as to the content of the plain text?
>I guess the message would best be several times the length of the
>bit mask for this to work.

I retracted this statement after being corrected via email.  It seems that
the scheme is a little more complicated than that.  It uses the IDEA cipher
and encrypts *that* key using RSA.  

It might still be weak on very, very long messages, but nowhere near as weak
as a simple bitmask.

Keith Lewis             klewis@mitre.org          "Mr. Cheap"
I don't dance to music; music dances to me.  Email me for my PGP key.
The above may not (yet) represent the opinions of my employer.
Newsgroups: sci.crypt
From: phr@telebit.com (Paul Rubin)
Subject: Re: Every Spy Should Carry a Bible
Organization: Telebit Corporation; Sunnyvale, CA, USA
	<PHR.92Oct1132531@napa.telebit.com>
	<1992Oct1.215048.25224@news.eng.convex.com>
Distribution: usa
Date: 2 Oct 92 16:55:14

In article <1992Oct1.215048.25224@news.eng.convex.com> gardner@convex.com (Steve Gardner) writes:

   >>Why not just go buy an HP-48 and replace the chip with your own chip
   >>that has everything you want. 
   >You want to use an unmodified, non-fancy, non-techno-geek, consumer
   >calculator identical to those used by millions of innocent people.
	   Not necessarily.  You want one that *looks* identical to "an 
	   unmodified, non-fancy, non-techno-geek, consumer [ etc. . . . ]"
	   If you are a spy and someone is suspicious enough to take apart
	   your TI calcuator you are in deep shit already.  


If they take apart your TI calculator and don't find anything,
you may be in deep shit but not as deep as if they *do* find something.
Newsgroups: sci.crypt
From: dla@athena (Don Alvarez)
Subject: Re: Message interception
Originator: news@nimaster
Organization: Princeton University
Date: Sat, 3 Oct 1992 18:39:58 GMT

In article <1992Oct2.203303.9914@vela.acs.oakland.edu> phkahler@vela.acs.oakland.edu (KAHLER PAUL H.) writes:

>I have a new idea on how someone (NSA for example) could intercept and read
>PGP (maybe other) encrypted messages.
>
>1) Modify PGP so that it only generates a small number of secondary keys.
>   Since the user is unaware of what key is used, he/she would never know.

If you are going to allow the bad guy to modify the user's copy of PGP
(or any other encryption routine), then of course the bad guy can win.
Forget PGP for the moment, and assume that you just have a generic
routine with access to the plaintext (your text editor, for example).
If you can't trust the routine, then you can never be confident that
the plaintext wasn't written to a file, inserted into a virus for
floppy-based distribution, squirted out through a modem while the
keyboard and phone were idle, or whatever.  I know your proposal
doesn't require access to the plaintext, but other parts of PGP do,
and if the bad guy can modify routines which have no access to
plaintext, he can certainly also modify other routines at the same
time.

Now for the rub:

Unless you have digitally signed cryptographically secure checksums of
all the software you run on your machine, you can't trust the machine
not to divulge your plaintext.  BUT even this won't help because you
have no way to trust that the digital signature computing software and
checksum computing software weren't the first things the bad guy modified.

>Please correct me if this is not possible. It is certainly a hell of a lot
>simpler than the other methods the paranoids were talking about.

Regarding your accusations of "paranoia", modern cryptography is
nothing more than a mathematical framework for debating the
*implications* of various paranoid delusions.  This is a completely
disjoint process from debating the *merits* of said paranoid
delusions.

You can't discuss cryptography without discussing the types of attacks
that the information may be subject to.  If you don't like having
people explain to you how a certain type of protocol is vulnerable to
a certain type of attack, then you might as well give up on the
subject of cryptography, because that is what it's all about.
>
>Paul
>
-don
dla@athena.princeton.edu

Newsgroups: sci.crypt
From: phkahler@vela.acs.oakland.edu (KAHLER PAUL H.)
Subject: Message interception
Organization: Oakland University, Rochester MI.
Date: Fri, 2 Oct 1992 20:33:03 GMT

I have a new idea on how someone (NSA for example) could intercept and read
PGP (maybe other) encrypted messages. This is simple based on how PGP works.
To refresh your memory, PGP doesn't actually use RSA, instead, the RSA key
is used to encrypt a second random key. It is this second key which is used
to encrypt the message (actual RSA would be very slow).

  Now suppose they (whoever THEY are) do the following:

1) Modify PGP so that it only generates a small number of secondary keys.
   Since the user is unaware of what key is used, he/she would never know.

2) Make sure this version of the program is widely distributed, or even
   get it to the ftp sites.

3) Messages can now be intercepted (copied) at any point along the way and
   decoded by simply trying all of the secondary keys (not many). i.e. skip
   the RSA decryption.

Please correct me if this is not possible. It is certainly a hell of a lot
simpler than the other methods the paranoids were talking about.

I suppose PGP could be obtained as source code and each person would have
to compile it themself. But how big a change would be needed to restrict
the number of secondary keys?  could it be overlooked anyway? (as you can
tell, I don't have source code, so I don't know.)

Notice, only the sender would need a fake copy of the program, for this to
work. And you can (sometimes) tell a lot from only one end of a conversation.

Just pretending to be paranoid... or am I?

Paul

Newsgroups: sci.crypt
From: "alan gahtan" <alan.gahtan@canrem.com>
Subject: triple des encryption
Reply-To: "alan gahtan" <alan.gahtan@canrem.com>
Organization: Canada Remote Systems
Distribution: sci
Date: 1 Oct 92 23:00:17 EST

Could someone please explain what is meant by "triple DES" encryption. 
Does it mean that the plaintext message is encrypted using the same 
password 3 times or does it mean the DES is used with three different 
passwords?

               Alan
---
  1st 1.01 #444  If there is no God, who pops up the next Kleenex?
--
Canada Remote Systems  - Toronto, Ontario
World's Largest PCBOARD System - 416-629-7000/629-7044
Xref: sparky sci.crypt:3524 alt.security:4492 alt.security.pgp:46
From: lewis@aera8700.mitre.org (Keith Lewis)
Newsgroups: sci.crypt,alt.security,alt.security.pgp
Subject: Re: pgp2.0 - what is an appropriate key length?
Date: 28 Sep 92 20:26:20 GMT
Organization: The MITRE Corporation

In article <1992Sep25.191759.25545@nevada.edu>, oliverm@nevada.edu (Moises Oliveira ) writes:
>I keep hearing that RSA uses the product of two big primes to produce a really
>big number that is hard to factor.  Appearently the diffuculty in factoring
>the product of two primes is what makes RSA so hard to crack.

Yes.

>Now, assume that the actual factoring is trivial by use of some mathematical
>method.  What good does it do you?  Exactly how does having the two prime 
>factors of some really big number do to help you crack RSA?
>
>In other words, if see someones public key, how can I find what really
>big number they used? And then after I factor it, what whould I do to the
>encrypted communications to return it to plain text?

You have two large primes, P and Q.
Let N = P * Q.  That's your "really big number".
Find a pair of numbers, E and D, such that mod(E * D, (P-1)*(Q-1)) = 1
You publish N and E as your public key.  To encrypt messages, calculate
    Y = mod(X ** E, N), where X is the input data

You keep N and D as your private key.  To decrypt messages, calculate
    X = mod(Y ** D, N), where Y is the encrypted data

If you have somebody's N and E, and you somehow factor N into P and Q, you
must then find a D that works in the above equality (a non-trivial task, I
think).  Then you can decrypt his/her messages.

>Finally, is the product of two primes method used in all public keys, or
>just in RSA? what about PGP?  What about the one the NSA and NIST produced.?

PGP is essentially RSA performed on a bitmask which is used repeatedly on
a single message.  I don't know about the others.

>If anyone has any books or other materials that they would reccommend for
>reading on the security of this type, I would appreciate it.

Check out the "Mathematical Games" column of _Scientific American_, August
1977, for a cursory examination of RSA.  Then August 1978 for a full-blown
article.

Keith Lewis             klewis@mitre.org          "Mr. Cheap"
I don't dance to music; music dances to me.  Email me for my PGP key.
The above may not (yet) represent the opinions of my employer.
Newsgroups: sci.crypt
From: xexeo@dxcern.cern.ch (Geraldo Xexeo)
Subject: Certification Authority?
Organization: CERN European Lab for Particle Physics
Date: Thu, 1 Oct 1992 15:39:15 GMT

Since some discussions on trusting keys
are already in the group.

1) How could we set-up an certification authority
equivalent to RSA?

2) How could this be done in a cooperative way?

3) How americans could profit of it without breaking
patent laws?

4) What will be the problems of this certification
authority?

5) How can we do it FOR FREE (altough the US$25 
charged by RSA is not too much).

The PGP manual suggests a "guerrila" style CA, but this
really means no CA, but just friend to friend trust.
If we want to have other uses for PGP, like certifying
software is not infected, we must trust someone that
is probably not a friend or a friend of a friend.

     Cheers,

             Jerry

-- 
-----------------------------------------------------------------------------
Geraldo Xexeo      |internet: xexeo@dxcern.cern.ch | "Cristo Redentor,    
CERN - PPE Division|bitnet:   gxexeo@cernvm.bitnet |  Bracos abertos sobre a
1211 Geneve 23     |decnet:   vxcern::xexeo        |  Guanabara...
Switzerland        |FAX:      (41) (22) 785 - 0207 |  Rio, eu gosto de voce!"
-----------------------------------------------------------------------------
Newsgroups: sci.crypt
From: kaufman@Xenon.Stanford.EDU (Marc T. Kaufman)
Subject: Re: PGP *2.0* available
Reply-To: kaufman@CS.Stanford.EDU
Organization: CS Department, Stanford University, California, USA
Date: 27 Sep 92 15:40:07 GMT

ritter@cactus.org (Terry Ritter) writes:
> In <9209252236.1.20681@cup.portal.com> a-boyles@cup.portal.com writes:

->I think Terry Ritter is underestimating the effort needed to successfully
->carry out the spoofing attack he describes.

> Look, I really want to get out of this discussion, but this is
> really quite outrageous.  We're talking about computers here.
> Once a decent spoofing program is written, how much does it "cost"
> to get it running on a bunch of nodes?  Perhaps the expense of
> visiting the various node owners and pulling out badges?

This entire argument has revolved around establishing the private key of
someone you haven't met, or can't meet, in person or by telephone.  Pray
tell, just why would you want to do that?  No matter how the person comes
across on newnews, he or she could be an agent provacateur or spy or...
I mean, the ultimate (and simplest) spoof is to just pretend to be someone
else when you are on the net.

Why would you attempt to set up a secret channel with someone you haven't
'vetted by other means?
-- 
Marc Kaufman (kaufman@CS.Stanford.EDU)
From: mdeale@zeus.calpoly.edu (Myron Deale)
Newsgroups: sci.crypt
Subject: Re: Irrational numbers as "strong" RNGs?
Date: 2 Oct 92 19:53:35 GMT
Article-I.D.: zeus.1992Oct02.195335.119303
Distribution: usa
Organization: California Polytechnic State University, San Luis Obispo

In article <1992Oct1.190441.15712@netcom.com> rcain@netcom.com (Robert Cain) writes:
>I believe the problem with using a known irrational number and a secret
>starting place as a key is that keys must be large to stop brute force
>and I don't think there is a way to just start generating digits from
>an arbitrary point without generating all the ones in between.  So while
>it would work, it would be computationally infeasable.  Someone please
>correct me if I am wrong.  I have wondered about this also.
>
>Bob Cain    rcain@netcom.com   408-358-2007

	This perhaps bring up the similar concept of cryptographically
secure pseudo-random number generators.  I remember reading one
scheme [Vazirani? or Blum?] which uses the equation
x[i+1] = x[i-1] ^ (x[i] * x[i]) mod N
where ^ is the xor operator, an indispensable operation.  Only a
fraction of the bits are secure ... on the order of Sqrt[ Log[2., N] ],
though this may be off by a constant.  You may produce a potentially
infinite series of secure bits ... and other useful properties.
	Anyone have better references?

-- Myron
From: sammy@anagld.analytics.com (Sam Blackburn)
Newsgroups: sci.crypt
Subject: Re: Proposed noise-based encryption method
Date: 30 Sep 92 22:26:48 GMT
Organization: Computer Sciences Corporation - Systems Engineering Division

rahdert@thrombus.seas.upenn.edu (Dave Rahdert) writes:

>The obvious disadvantage of this method is the large amount of information 
>which must be exchanged by the two parties beforehand.  You must generate a
>key which is at least as big as the chunk of information you want to encrypt.

This is the problem with your idea.  In "The Codebreakers" this method is 
known as a "one-time pad" which are unbreakable.  Their problem is the logistics
required to properly use the system.  Key distribution is another problem.  In
your idea there would have to be a face to face meeting to exchange CDs. What
happens if you mail the CD out?  It could be copied or lost or damaged, etc.

All in all, your idea seems to be a sound one but still suffers from a 
logistical standpoint.

                                                               o
Sam Blackburn                                                    \
Internet:   sammy@sed.csc.com                                  \O/
Compuserve: 76300,326                     ||====================|====||
GEnie:      SAMMY                         ||-+-+-+-+-+-+-+-+-+-/\+-+-||
                                          ||===================\=\===||
                                          ||                         ||
                                          || Kill or be killed.      ||
Newsgroups: sci.crypt,alt.security,alt.security.pgp
From: marti@nugget.inf.ethz.ch (Robert Marti)
Subject: Re: pgp2.0 - what is an appropriate key length?
Organization: Dept. Informatik, Swiss Federal Institute of Technology (ETH), Zurich, CH
Date: Tue, 29 Sep 1992 07:43:32 GMT

In article <1992Sep28.160834.5578@neptune.inf.ethz.ch>, I wrote
in connection with the RSA public key system:

|> The function returns the secret (private) exponent d which is
|> the multiplicative inverse of e in the finite field of numbers
|> in the range [0,(p-1)(q-1)-1].

Before anyone else points this out to me: the integers in the
range [0,(p-1)(q-1)-1] are of course not a field (since the
modulus is not a prime number) but only a ring.  However, e is
"constructed" in such a way that a multiplicative inverse modulo
(p-1)(q-1) exists.

-- 
Robert Marti                    |  Phone:    +41 1 254 72 60
Informationssysteme             |  FAX:      +41 1 262 39 73
ETH-Zentrum                     |  E-Mail:   marti@inf.ethz.ch
CH-8092 Zurich, Switzerland     |