HDTenEightyP/NetNews huggingface dataset:
From: cbbrowne@csi.uottawa.ca (Christopher Browne)
Subject: Re: Deterring plaintext attacks
Organization: Dept. of Computer Science, University of Ottawa
Date: Thu, 5 Nov 92 23:20:09 GMT

In article <1992Nov5.154602.28033@ulysses.att.com> smb@ulysses.att.com (Steven Bellovin) writes:
>In article <1992Nov5.000740.1755@qiclab.scn.rain.com>, leonard@qiclab.scn.rain.com (Leonard Erickson) writes:
>> gilchr@ee.ualberta.ca (Andrew Gilchrist) writes:
>> 
>> >What are theoretic ways to deter a plaintext attack?
>> 
>> >i.e. The opponent is given two ciphertext messages, the plaintext of
>> >the first message, and the encryption method.
>> 
>> 
>> >Now, obviously the longest key in the world will not help.
>> 
>> >How does one protect the key, so that it can be reused.
>> 
>> You *can't*.
>That's not true at all.  Rather, it's not true for most types of
>cryptosystems.  Consider DES -- as far as the non-classified world
>knows, it's immune to known-plaintext attacks.  Even if you run DES
>in output feedback mode, generating an XOR stream similar to what
>the original poster asked about, the *key* is the 56 bits you fed
>into the DES engine, not the output from DES acting as a cryptographically
>strong random number generator.

(a) If you add some "salt" to the plaintext, it helps.  I.e. - adding some
"really" random material to the plaintext can be helpful.  This is the
sort of thing that's done with UNIX passwords - DES is used to encrypt
a combination of (a) zeros, and (b) a random bitstring.  This means that
even if you use the same password on different accounts, the entry in
/etc/passwd won't be the same on the different accounts.

Thus, here the issue isn't "protecting the key", the issue is "protecting 
the plaintext."

(b) It looks to me like the plaintext issue relates to making sure that
the encryption is powerful enough.

If your encryption can keep a compressed binary file from being decrypted, 
that's probably no big deal.  Since it might be difficult to make sense
of the FINAL product, it's probably easy to make it unbreakable.

The REAL test is if you can keep secret a set of text that should be
``easy to decrypt,'' or at least, easier than average.  If the cipher
can defy analysis on easy text (better still, KNOWN text), then it's
probably quite safe.

I.E.: The BEST(/worst) case scenario would be as follows:
Assume:
(a) I have a plaintext copy of message M.
(b) I have an encrypted copy of message M, E(K,M).
(c) I don't know the key, K

If the cipher scheme is REALLY good, I won't be able to determine the
key, K, even though I have M, E(K,M) and information on the encryption
function E.

This, of course, is the point of RSA - even given messages and public
keys, it's very hard to determine the private key.

And DES seems to be pretty resistant to attack even of this type.

-- 
Christopher Browne                |     PGP 2.0 key available
cbbrowne@csi.uottawa.ca           |===================================
University of Ottawa              |  The Personal Computer:  Colt 45
Master of System Science Program  |  of the Information Frontier
Newsgroups: sci.crypt
From: pmetzger@snark.shearson.com (Perry E. Metzger)
Subject: Re: privacy
Organization: /usr/local/lib/news/organization
Distribution: na
Date: Fri, 6 Nov 1992 00:11:36 GMT

awk@sequent.com (Dave Aucsmith) writes:
>marc@tanda.isis.org (Marc Thibault) writes:
>
>>        Sometimes it truly is a joy to be living north of the 49th. On
>>        a day when many of us are celebrating the recent saving of our
>>        Charter of Rights and Freedoms from being watered down by a
>>        venal bunch of self-interested politicians, I would like to
>>        ask two questions:
>
>>     1. Given that the NSA has classified secret codes as armament,
>>        doesn't your Second Amendment right to bear arms therefore
>>        also guarantee your right to use secret codes?
>
>	The right to bear arms does not extend to the right to posses
>	a surface to air missle.  The courts have ruled that the Second
>	Amendment can have reasonable restraints placed on it.  What
>	is reasonable is for a court to decide.

Actually, this is false. There have been no such rulings to my
knowledge. There has simply been an effort to out and out ignore the
second amendment. The last case that I know of that successfully
reached the supreme court was the Miller case in the 1930s, in which
it was ruled that since the guy claiming the right to own a sawed-off
shotgun hadn't shown up (their side literally did not appear), the
court would assume that the weapon was not a military one and thus
might not be covered. You heard that bit right, by the way -- the
ruling implied that it is military weaponry, and not sporting
weaponry, that is covered by the amendment. However, as all of this
has gone completely away from the original topic, I suggest those who
are interested take it up in talk.politics.guns instead.

--
Perry Metzger		pmetzger@shearson.com
--
"They can have my RSA key when they pry it from my cold dead fingers."
Libertarian Party info: Phone 1-800-682-1776, E-Mail 345-5647@mcimail.com
From: mcclary@netcom.com (Michael McClary)
Newsgroups: sci.crypt
Subject: Re: A One-Time Way to Thwart Key Registration...
Keywords: one-time pad
Date: 11 Nov 92 01:13:31 GMT
Article-I.D.: netcom.1992Nov11.011331.21831
Organization: Netcom - Online Communication Services (408 241-9760 guest)

In article <pcw.720808942@access.digex.com> pcw@access.digex.com (Peter Wayner) writes:
>
>>1) Can you trust the criminals to provide the keys to their data and to use
>>   those keys (and no others) when transmitting incriminating data?  If not,
>>   what's the point?
>
>Actually, my favorite solution to this criminal problem is to use
>a one-time pad. Then it is possible to come up with two keys. One
>that decrypts the conversation into a benign one and one that decrypts
>it into the real message.

This works if they demand the key after the message was sent.  It's a tad
harder if you have to register the key in advance of composing the message.
B-)
-- 
=	=	=	=	=	=	=	=	=	=
Michael McClary						mcclary@netcom.com
For faster response, address electronic mail to:	michael@node.com
Newsgroups: sci.crypt
From: gilchr@ee.ualberta.ca (Andrew Gilchrist)
Subject: Re: Encrypted phones, keys, taps, ...
Organization: University Of Alberta, Edmonton Canada
Date: Mon, 9 Nov 1992 11:46:08 GMT

While I don't argue that such a sampling/compression/encryption/
transmission/decryption/decompression/reconstruction could be done virtually
in real time on a typical phone line with a lot of funding, I will need
some math and some specifications for devices capable of carrying this out
reliably on an analog cellular network before I am convinced.  I don't have
bandwidth specs or s/n values for cellular transmissions, so I can't do this
for myself.

As for scramblers, I'd like to point out that digital scrambling of phone
lines (not subscriber lines generally) predates the DES.

Xref: sparky sci.crypt:4595 alt.society.civil-liberty:6524
Newsgroups: sci.crypt
Subject: Re: Limits on the Use of Cryptography?
From: a_rubin@dsg4.dse.beckman.com (Arthur Rubin)
Date: 13 Nov 92 16:48:52 GMT
Organization: Beckman Instruments, Inc.

In <1992Nov12.195827.1@zodiac.rutgers.edu> leichter@zodiac.rutgers.edu writes:

>BTW, if you knowingly boobytrap your safe so that it destroys its contents
>when the police lawfully try to open it, you can probably be charged with
>destruction of evidence.  (If you boobytrap your safe in a way that kills
>a police officer trying to open it, you will be charged and likely convicted
>of at least manslaughter.  Think long and hard about explosives, incendiaries,
>and similar nasties.)

Agree with the latter, but not the former.  You have no duty to assist the
police (under hardly any circumstances); if the police try to open it, and
thereby destroy the contents, you have a probable claim for damages against
the government, rather than there being any charge against you.

...

>You don't need to bring a PC into this.  People have been hiding records for
>years.  Sometimes they even get away with it.  How far away can the hard
>drive be hidden?  If it's anywhere in your house, it will be found - under
>a warrant, the police can literally disassemble your house and everything
>in it into pieces too small to hold a drive.  It's your problem to put it all
>back together after.  Buried it on your property?  Metal detectors are pretty
>good, you know.  If that fails, we'll just start digging.  It's been done;
>it'll be done again.

It's still illegal.  Courts have found that damages caused by a "legal"
search are still illegal acts.  (However, you'll probably die before you
collect.)

--
Arthur L. Rubin: a_rubin@dsg4.dse.beckman.com (work) Beckman Instruments/Brea
216-5888@mcimail.com 70707.453@compuserve.com arthur@pnet01.cts.com (personal)
My opinions are my own, and do not represent those of my employer.
My interaction with our news system is unstable; please mail anything important.
Xref: sparky sci.crypt:4391 comp.org.eff.talk:6804 alt.privacy:2111 talk.politics.guns:23598
From: rcain@netcom.com (Robert Cain)
Subject: Re: Encrypted phones, keys, taps, ...
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Wed, 11 Nov 1992 05:17:20 GMT

Can anyone provide a good reference on CELP and/or companies that sell
DSP software that can get intelligable voice down to within v.32bis?

Thanks,

Bob
-- 
Bob Cain    rcain@netcom.com   408-358-2007

        "One can learn to be alone, even enjoy it, but let intimacy
         break that solitude, even briefly, and one must start all
         over again."

                                                     Elia Kazan


               PGP 1.0 or 2.0 public key available on request.
Newsgroups: sci.crypt,comp.org.eff.talk,alt.privacy,talk.politics.guns
From: starr@genie.slhs.udel.edu (Tim Starr)
Subject: Re: Registered Keys - why the need?
Organization: UDel, School of Life & Health Sciences
Distribution: inet
Date: Sun, 8 Nov 1992 09:30:59 GMT

In article <palmer.721081324@news.larc.nasa.gov> palmer@icat.larc.nasa.gov (Michael T. Palmer) writes:
}By the way, a MAJOR HUGE difference between automobiles and guns/crypt
}is that driving a car on the highways of a state is a privilege, whereas
}bearing arms in defense of self/family/country and communicating with
}others privately are RIGHTS guarranteed (not granted) by our constitution.

Actually, this is a statist myth.  In common law, the law of the land, driving
is indeed a right, not a privilege, the cant of drivers' ed teachers, traffic
cops and judges notwithstanding.

}The state has an interest in registering automobiles, so that it can
}exercise the authority granted it by its citizens regarding vehicular
}rules and regulations.

We've granted no such authority, therefore the state has no such just power,
interests notwithstanding.

}This is why the mention of firearms/crypto key registration makes people
}hopping mad - we know what the long term impact of letting such laws get
}passed will be.  The government will assume powers not given it by the
}people.

Like the abovementioned power to register cars.


Tim Starr - Renaissance Now! - Think Universally, Act Selfishly
starr@genie.slhs.udel.edu

"True greatness consists in the use of a powerful understanding to enlighten
oneself and others." - Voltaire
From: TSOS@uni-duesseldorf.de (Detlef Lannert)
Newsgroups: sci.crypt
Subject: Re: Registered Keys - why the need?
Date: Tue, 10 Nov 1992 10:00:27 GMT
Organization: Universitaetsrechenzentrum, Heinrich-Heine-Universitaet, Duesseldorf
NNTP-Posting-Host: lannert.rz.uni-duesseldorf.de

>>       The major difference between guns and cars are that licensing and 
>>registration have not been suggested as a way to reduce the numbers of cars 
>>in private hands.  This has been said a number of times for guns. [...]

I'm afraid that the comparison of cryptographic key registration to the
registration of cars and guns can be misleading.

Possessing (and using) a car or a gun is a privilege and can infringe on
other people's rights. (Think of the possible fatal consequences of any
misuse; but even apart from the worst case, you would certainly get out
of my way if I moved in your direction, in a car/holding a gun, with a
grim look on my face, and you were unprotected ...)

So the main reason why a registration of cars/guns is compulsory in most
countries lies in the dangerousness of the thing itself; possessing and
(immorally) using either object threatens the other members of the
community. [I'm not going to address the question whether a ban or
registration of firearms is appropriate or not!]

Free communication, however, is IMHO not a dangerous device at all, and
therefore I don't see why it should be controlled by the authorities.

It's not to be compared with driving a motor car; rather with walking,
if you really want an analogy. (How about this: People shouldn't be
allowed to walk about and carry bags or even locked suitcases; they
could use the contents of these to commit a crime; and there have been
a number of cases reported where people actually transported daggers,
submachine-guns, or drugs ...)

Please don't engage in (albeit interesting) discussions about the
registration of guns, cars, planes, or what-have-you, thereby creating
false analogies and opening up new wealths of arguments for the
pro key registration lobby.

[This is not a flame and not directed at anyone; I'm just concerned.]
--
Detlef Lannert      DC3EK      E-Mail: tsos@rz.uni-duesseldorf.de
"Gedanken sind nicht stets parat,
man schreibt auch, wenn man keine hat."             Wilhelm Busch
Newsgroups: sci.crypt
From: pmetzger@snark.shearson.com (Perry E. Metzger)
Subject: Re: Encrypted phones, keys, taps, ...
Organization: /usr/local/lib/news/organization
Date: Fri, 6 Nov 1992 01:23:30 GMT

Someone posted an idea about digitally encrypting phones, cellular
phones in particular, by digitizing the signal and using a
conventional end to end cryptosystem, following which we got this...

gilchr@ee.ualberta.ca (Andrew Gilchrist) writes:
>
>The system you describe cannot be implemented on current cellular
>phone systems in real-time.

Mr. Gilchrist is rather mistaken.

In fact, you can buy systems to digitally encrypt your cellular
communications right now. AT&T sells such a unit, for instance,
although they will only sell the ones that use really good encryption
to Government agencies. The unit in question is just one of their
normal units for digital encrypted telephony over normal phone lines
with a cellular transmitter attached.

There is nothing infeasable about building encrypted phone units.
Modems now hit 14 kilobaud and even higher with the new V.Fast units
in test (24kbaud is my understanding), whereas excellent voice can be
transmitted digitally over a 9.6kbaud bandpass given modern
compression techiques like CELP (codebook excited linear prediction).
Given the ability to digitize voice in real time and compress it down
so it needs low bandwidth, all one need do is apply an encryption
system (most conventional cryptosystems work orders of magnitude
faster than is needed even on wimpy hardware) and squirt the signal
out a V.32bis or similar modem, and, voila, encrypted telephony, and
in real time.

>A standard phone scrambler would be much easier to get/use/etc.

If "standard" means analog, well, analog phone scramblers are almost
all easily broken, and are pretty poor in general. Why use one when
digital techniques that are virtually unbreakable are available?
--
Perry Metzger		pmetzger@shearson.com
--
"They can have my RSA key when they pry it from my cold dead fingers."
Libertarian Party info: Phone 1-800-682-1776, E-Mail 345-5647@mcimail.com
Newsgroups: sci.crypt
From: ken@halcyon.com (Ken Pizzini)
Subject: Encryption modes of block ciphers (was: Re: is this bad?)
Organization: The 23:00 News and Mail Service
Date: Thu, 12 Nov 1992 21:42:00 GMT

In article <1992Nov12.011804.12685@news.Hawaii.Edu> newsham@wiliki.eng.hawaii.edu (Timothy Newsham) writes:
>when few replies mentioned I should just use the CBC mode of DES
>it became apparent to myself that I hadn't stated my goals well
>enought either...

No, not CBC mode; CFB mode seems to do what you want.

>goal:  an encryption scheme that gives me the strength of DES
>along with the ability to send single characters one at a time.
>Also it would be nice if the scheme lended itself well to
>sending 7-bit characters in only 7 bits.

Cipher feedback mode allows you to send k bits (0 <= k <= blocksize)
at a time using a block cipher.  The gist is as follows:

The two ends agree on the session key and an initial-input vector
which they each feed through the block cipher.  The sender XORs the
high-order k bits of the output with the k bits of plaintext and
transmits the result to the receiver, who will do the same XOR to
recover the plaintext.  In addition, both ends take the ciphertext of
this iteration and append it to the end of the previous input vector
after first shifting the input vector k bits (and throwing away the
high-order k bits).  This modified input vector is re-encrypted with
the session key, setting up the output to be ready for the next
plaintext.

		--Ken Pizzini
Newsgroups: sci.crypt
From: neergaar@schaefer.math.wisc.edu (Dude)
Subject: Re: Limits on the Use of Cryptography?
Organization: Univ. of Wisconsin Dept. of Mathematics
Date: Wed, 11 Nov 92 14:36:15 GMT

piet@cs.ruu.nl (Piet van Oostrum) writes:

>>>>>> ritter@cactus.org (Terry Ritter) (TR) writes:

>TR>     The police bust an alleged child molester, and take possession
>TR>     of his PC.  They believe that the hard drive contains a full
>TR>     database of young kids who have been *or may be* assaulted.
>TR>     That database is enciphered.

>Yeah and would you think he would just encipher it with a registered key?

The point is, if he doesn't, you nail him on *that* charge instead!

>Or think of the following scenario: Het isn't so stupid to put the database
>in his computer, but he has it on paper in a vault with a combination lock.
>What is the difference? (by the way, the vault destroys its contents when
>it is forcefully opened).

The thing is, there are people in the world who are less careful than they
could be.  They don't even use encryption, but they *do* use a computer.  
They just change all the filenames.  There *are* some clever ones who do 
pretty much what Terry Ritter suggested.  His scenario isn't so far out, 
IMHO.

On the other hand, the idea that every criminal has access to and regularly
uses some kind of vault complete with a self destruct mechanism . . . that's
maybe a little less likely.
-- 
I really don't make any claim at all to know what I'm talking about.
Actually, I make no claim to know what YOU'RE talking about, either.
In fact, now I've forgotten what we were talking about . . .
Newsgroups: sci.crypt
From: caronni@nessie.cs.id.ethz.ch (Germano Caronni)
Subject: Re: time-release keys
Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
Date: Fri, 13 Nov 1992 03:06:44 GMT

In article <1dohq8INNbs4@transfer.stratus.com> cme@ellisun.sw.stratus.com (Carl Ellison) writes:
>
>Does anyone out there have an idea of how to achieve this time-release of
>info (probably of an encryption key rather than of a body of text) with the
>independence of human good behavior but a decent time interval?

How about encrypting such news with an RSA-Key or so, and just forget
the secret key. If anybody cares about the information, he can gather
computing powers to factorize the public key, and then can read the public
encrypted message. Just hope that computers are not fast enough into
break the key in already 10 years :-) (Yes , I know, this is a silly idea:-))

Just for my curiosity: How would you assure the information was stored in
an archive,which will be openend in 30 years ? In every good thriller about
spies, there are files which are not recorded anywhere .... :-)

Second Idea: Assuming the information is reliably put into a kind of
achive and the problem lies only there to get people to 'open' the
archive after 30 years, make this independent from people.
Any kind of physical process wil do: Place a radio-mirror in about
15 Lightyears distance (yes - silly - I know) and just send out the message
you want to have publicly available after 30 Years. Or bury it somewhere
where erosion will let it get to daylight after 30 years. Put the information
in space, and give it a kind of orbit, which with high probability comes back
to you after 30 years. In the meantime distance shall be as big as possible :-=)

Dont take me too serious ;^)

		gec
-- 
Instruments register only through things they're designed to register.
Space still contains infinite unknowns.

Germano Caronni    caronni@nessie.cs.id.ethz.ch
Newsgroups: sci.crypt,alt.folklore.urban,alt.politics.usa.constitution
From: symanzik@pigeon.egr.msu.edu (Edward Symanzik)
Subject: Re: U.S. Constitution
Organization: College of Engineering, Michigan State University
Date: Fri, 6 Nov 92 13:43:26 GMT

In article <1992Nov5.121745.21162@ulysses.att.com>, smb@ulysses.att.com (Steven Bellovin) writes:
|> In article <WCS.92Nov4184054@rainier.ATT.COM>, wcs@anchor.ho.att.com (Bill Stewart +1-908-949-0705) writes:
|> > There's been one Amendment since then, restricting Congress's ability
|> > to raise its own pay.  Originally proposed in the early 1800s,
|> > and not having a time limit for its adoption, it was finally approved
|> > by 3/4 of the states a few months ago.
|> 
|> Yes, and I think it's going to make for an interesting Supreme Court case.
|> I seem to recall an earlier court ruling that ratifications be ``substantially
|> contemporaneous'', which sure doesn't apply here.  And a lawsuit has been
|> filed under that amendment, charging that a recent Congressional pay
|> raise violates it.

Am I missing something here?  Didn't we just have an election?

/Ed Symanzik
Newsgroups: sci.crypt
From: neergaar@schaefer.math.wisc.edu (Dude)
Subject: Re: ATM security question
Organization: Univ. of Wisconsin Dept. of Mathematics
Date: Fri, 6 Nov 92 13:44:20 GMT

oppedahl@panix.com (Carl Oppedahl) writes:

>In <1992Nov5.184546.5854@ulysses.att.com> tom@ulysses.att.com (Tom Smith) writes:

>>On another newsgroup, there is a lot of discussion about Automatic
>>Teller Machines and the Personal Identification Number (PIN) associated
>>with an account/card.  There is controversy about whether or not
>>an encrypted version of the PIN is encoded onto the magnetic stripe
>>on the card.

>Which newsgroup?  I'd like to follow that.

ditto.

>Yes, there is.  This means the ATM can match your card to the PIN
>you entered at the ATM, even if the phone lines are cut.  Scary, huh?

>Well, it means the ATM can match _if it has the key_.  Each
>issuer has its own key.  The ATM you visit probably can match the
>card PIN with the entered PIN only if the bank that runs it issued
>your card.

I read somewhere on the net that all PINs are encrypted with the *same* *key*
so that any ATM can match any card to its PIN.  Can anyone verify or 
disprove this?

-- 
I really don't make any claim at all to know what I'm talking about.
Actually, I make no claim to know what YOU'RE talking about, either.
In fact, now I've forgotten what we were talking about . . .