Cryptography-Digest Digest #733, Volume #13 Thu, 22 Feb 01 09:13:01 EST
Contents:
Re: Is there an algorithm to sequentially enumerate all transcendental (jtnews)
Re: What does tempest stand for. (fvw)
Re: Super strong crypto ("Bryan Olson")
Re: Metallurgy and Cryptography (Derek Bell)
Re: Metallurgy and Cryptography (Derek Bell)
Re: The Key Vanishes: Scientist Outlines Unbreakable Code, Read it and Weep Boys
("Randoman")
Re: The Key Vanishes: Scientist Outlines Unbreakable Code, Read it and Weep Boys
(Nuno Souto)
Re: What does tempest stand for. (John Savard)
Re: The Key Vanishes: Scientist Outlines Unbreakable Code, Read it and Weep Boys
(Charles Blair)
----------------------------------------------------------------------------
Date: Thu, 22 Feb 2001 03:21:17 -0500
From: jtnews <[EMAIL PROTECTED]>
Crossposted-To: sci.math
Subject: Re: Is there an algorithm to sequentially enumerate all transcendental
John Savard wrote:
> Although there is no way to sequentially enumerate _all transcendental
> numbers_, there is a way (called Godel numbering) to sequentially
> enumerate all possible mathematical expressions.
>
> That will _not_ help you, however, to find a short mathematical
> expression to represent an arbitrary string of digits.
Can you give some references on the web
or in a book that goes over Godel numbering.
I'm very interested in how to sequentially enumerate
all possible mathematical expressions.
Thanks.
--
My U.S. Federal Gov't Budget Proposal for 2001 and Beyond
http://geocities.com/jtnews_bellatlantic_net/budget.html
------------------------------
From: [EMAIL PROTECTED] (fvw)
Subject: Re: What does tempest stand for.
Reply-To: [EMAIL PROTECTED]
Date: Thu, 22 Feb 2001 09:45:41 GMT
[EMAIL PROTECTED] (Mark Healey) wrote:
>I know that "tempest" is an acronym (really T.E.M.P.E.S.T.) but I
>forgot what it stands for. Surprisingly this isn't in any of the
>online sources I could find.
everything2.com gives the answer to your question (and the answer to
several million others you don't want to ask):
Transient Electromagnetic Pulse Surveillance Technology.
--
Frank v Waveren Fingerprint: 0EDB 8787
fvw@[var.cx|dse.nl|stack.nl|chello.nl] ICQ#10074100 09B9 6EF5 6425 B855
Public key: http:[EMAIL PROTECTED] 7179 3036 E136 B85D
------------------------------
From: "nospam"@"nonsuch.org" ("Bryan Olson")
Subject: Re: Super strong crypto
Date: Thu, 22 Feb 2001 10:26:37 GMT
Douglas A. Gwyn wrote (in the entirety):
>Bryan Olson wrote:
>> The key changes in real systems are there to limit the damage
>> from exposed keys; ...
>
>No.
If you read my post, you'll see I was specifically asking
for justification for what you had written. You had a
"natural lifetime" for a key, somehow related to unicity
distance. I don't see what responding with yet another
unjustified proclamation is supposed to accomplish.
--Bryan
------------------------------
From: Derek Bell <[EMAIL PROTECTED]>
Subject: Re: Metallurgy and Cryptography
Date: 22 Feb 2001 11:48:11 -0000
Trevor L. Jackson, III <[EMAIL PROTECTED]> wrote:
: There may be a hidden name/occupation relationship. Consider hatters.
: Carrol's Mad Hatter and the phrase "mad as a hatter" derive from the
: effects of the mercury used to produce felt hats. Perhaps the crypto
: Names derive from ancestral occupations that had beneficial effects on the
: descendants.
: ;-)
Feedback, the humour column of _New Scientist_, coined a term
for this a few years ago: nominative determinism. They still get
contributions for it!
Derek
--
Derek Bell [EMAIL PROTECTED] |"Usenet is a strange place."
WWW: http://www.maths.tcd.ie/~dbell/index.html| - Dennis M Ritchie,
PGP: http://www.maths.tcd.ie/~dbell/key.asc | 29 July 1999.
|
------------------------------
From: Derek Bell <[EMAIL PROTECTED]>
Subject: Re: Metallurgy and Cryptography
Date: 22 Feb 2001 11:49:18 -0000
Tad Johnson <[EMAIL PROTECTED]> wrote:
: Hello All ---
: I just realized something:
: Don COPPERsmith...
: Bob SILVERman...
: Benjamin GOLDberg...
: What the heck is going on here?
No relations to the author of _Copper, Silver, Gold: an
indestructable metal alloy_? :-)
Derek
--
Derek Bell [EMAIL PROTECTED] |"Usenet is a strange place."
WWW: http://www.maths.tcd.ie/~dbell/index.html| - Dennis M Ritchie,
PGP: http://www.maths.tcd.ie/~dbell/key.asc | 29 July 1999.
|
------------------------------
Reply-To: "Randoman" <[EMAIL PROTECTED]>
From: "Randoman" <[EMAIL PROTECTED]>
Subject: Re: The Key Vanishes: Scientist Outlines Unbreakable Code, Read it and Weep
Boys
Date: Thu, 22 Feb 2001 11:54:54 -0000
I think I'm missing something.
How do sender and received ensure that they are synchronised so that they
each use the same portion of the random stream as keys?
If there's some kind of synchronisation signal, what's to stop an
eavesdropper intercepting the sync. signal and logging the random stream at
the same time?
Thanks,
Gerald
<[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]...
> From the article at:
> http://www.nytimes.com/2001/02/20/science/20CODE.html?pagewanted=all
>
> February 20, 2001
> The Key Vanishes: Scientist Outlines Unbreakable Code
> By GINA KOLATA
>
> A computer science professor at Harvard says he has found a way to
> send coded messages that cannot be deciphered, even by an all-powerful
> adversary with unlimited computing power. And, he says, he can prove
> it.
>
> If he is right, and he does have some supporters, his code may be the
> first that is both practical and provably secure. While there are
> commercially available coding systems that seem very hard to break, no
> one can prove that they cannot be cracked, mathematicians say.
>
> In essence, the researcher, Dr. Michael Rabin and his Ph.D. student
> Yan Zong Bing, have discovered a way to make a code based on a key
> that vanishes even as it is used. While they are not the first to have
> thought of such an idea, Dr. Rabin says that never before has anyone
> been able to make it both workable and to prove mathematically that
> the code cannot be broken.
>
> "This is the first provably unbreakable code that is really
> efficient," Dr. Rabin said. "We have proved that the adversary is
> helpless."
>
> Dr. Richard Lipton, a computer science professor at Princeton, who is
> visiting this year at the Georgia Institute of Technology, said, "It's
> like in the old `Mission Impossible,' where the message blows up and
> disappears."
>
> Someone who uses one of today's commercially available coding systems,
> Dr. Lipton explained, uses the same key - mathematical formulas for
> encoding and decoding - over and over. Eventually, they may be forced,
> perhaps by a court order, to give up the key. Or the key may be
> stolen. But with Dr. Rabin's system, the message stays secret forever
> because the code uses a stream of random numbers that are plugged into
> the key for encoding and decoding. The numbers are never stored in a
> computer's memory, so they essentially vanish as the message is being
> encrypted and decrypted.
>
> "If someone walks into my office with a court order or if they put a
> gun to my head they still could not read my conversations," Dr. Lipton
> said.
>
> In a sense, say some mathematicians and computer scientists, Dr. Rabin
> may have solved the ultimate problem in cryptography, one that has
> driven research for centuries: finding a provably unbreakable code
> that is also practical. But, they say, the paradox is that the
> discovery has come at a time of vigorous debate over whether such a
> code will make much difference in keeping communications private.
>
> Some say that a provably unbreakable code could have profound effects,
> keeping secret messages secret forever. But others say that codes
> today are already so good that there is little to be gained by making
> them provably, rather than just probably, unbreakable.
>
> For now, Dr. Rabin's idea is simply a scheme backed up by a
> mathematical proof that he has been presenting to scientists at
> seminars. No company is lurking in the background to sell it, and Dr.
> Rabin says he has no commercial interests in it.
>
> "I never commercialize anything," Dr. Rabin said. "I am not in that
> business." Instead, he said, he did the work because it was a
> challenge.
>
> Dr. Rabin's idea is simplicity itself, at least in the world of
> encryption. Previous coding methods rely for their security on the
> limitations of computing power. They assume that if breaking a code
> requires enough calculations, even the best computers will not be able
> to do it.
>
> But, Dr. Rabin said, there is no proof that such codes are secure.
> Their security hinges on the belief that no one will find a shortcut
> to doing the calculations. It is always possible that such a shortcut
> exists, waiting to be discovered by a clever mathematician.
>
> Dr. Rabin relies instead on the limits of memory banks in computers.
> No matter how powerful a computer is, no computer can store an
> unlimited amount of data. And yet that is what is required for an
> eavesdropper to break his code.
>
> The coding starts with a continuously generated string of random
> numbers, say from a satellite put up to broadcast them or from some
> other source. The numbers can be coming by at an enormous speed - 10
> million million per second, for example.
>
> The sender of a message and its recipient agree to start plucking a
> sequence of numbers from that string. They may agree, for example, to
> send a message, encoded with any of today's publicly available
> encryption systems saying "start" and giving instructions on capturing
> certain of the random numbers. As they capture the numbers, the sender
> uses them to encode a message, and the recipient uses the numbers to
> decode it.
>
> An eavesdropper can know the mathematical formula used to encode and
> decode, but without knowing the exact sequence of random numbers that
> were used in the formula to send a particular message, the
> eavesdropper cannot decode the message. And the only way to have that
> sequence is to just happen to be storing numbers from the unending
> stream at exactly the right moment.
>
> If the eavesdropper, for example, had a secret way to decode the
> message saying "start" and it took a minute to do the calculation
> needed to decode it, it would be too late by the time the eavesdropper
> got going. The sender and recipient would already have their string of
> numbers and that string of numbers, once broadcast, could never be
> retrieved. It would be infeasible to store the endless string of
> numbers in any computer and so they are essentially gone forever.
>
> Often, Dr. Rabin said, eavesdroppers will capture and store encoded
> messages hoping to decode them at later, either when computers have
> improved - making it easier to do the calculations to break a code -
> or when the method for encoding and decoding is known, perhaps because
> it has been stolen. But, he said, messages encoded with his system can
> never be broken by these means because the random numbers used in
> encoding and decoding are used once and are never stored.
>
> "That is why I call it `everlasting security,' " he said.
>
> Dr. Richard DeMillo, chief technology officer at Hewlett-Packard, said
> that what interested him about the scheme was that it "reshuffles the
> policy deck."
>
> "Normally," he explained, "agencies put the burden of wiretapping on
> the carrier." A telephone company, for example, would have to allow an
> agency like the Federal Bureau of Investigation to listen in on coded
> material. But with this system, the agency would still have the burden
> of trying to capture the appropriate stream of random numbers, a task
> that would be technologically infeasible.
>
> Dr. Lipton also said the scheme could thwart law enforcement agencies.
>
> "If I'm saying to you, `Buy 1,000 shares of I.B.M., I'm sure it's
> going to go up,' " he said, "and if that was an insider trading
> situation, five years from now the F.B.I. could go after you."
>
> If the agency had the encrypted message in hand, it could demand the
> key to read it, he said. But, Dr. Lipton said, if the random numbers
> used to encode were used once and never stored, the agency would be
> hamstrung. "It changes the ground rules," he said.
>
> Dr. Lipton added that, as a computer scientist, he appreciated the
> proof that the code could not be broken. "Michael's big contribution
> has been the proof that the system actually works," he said. "It's one
> of those things that sounds obvious but the mathematics is quite
> hard."
>
> Of course, what is good for those who want privacy may not be good for
> law enforcement. Even the cryptography systems sold today are a
> problem for the F.B.I. "Uncrackable encryption allows drug lords,
> terrorists and even violent gangs to communicate about their criminal
> intentions without fear of outside intrusion," the F.B.I. director,
> Louis J. Freeh, told the Senate in 1998, according to a transcript
> from the Federal Document Clearing House. "This type of encryption
> also allows these same people to maintain electronically stored
> evidence of their crimes beyond the reach of law enforcement."
>
> Still, some computer experts said that while it might be interesting
> in theory to have a provably unbreakable code, the practical
> importance of Dr. Rabin's code may be minimal.
>
> Some, like Dr. Dorothy Denning, a computer science professor at
> Georgetown, and Dr. Cipher Deavours, a professor of computer science
> and mathematics at Kean University in Union, N.J., said the code was
> simply impractical for large messages. The larger the message, the
> longer the string of random numbers needed to encode it, and the more
> difficult it would be to send.
>
> "It's a cute idea, but it's simply unmanageable," Dr. Deavours said.
>
> Others, like Dr. Lipton, disagreed. "I think it is quite practical,"
> he said. And Dr. Rabin insisted that computers would have no problem
> with the encryption scheme, even with long messages that were sent
> among a large group of people.
>
> Beyond the question of whether the system would work in practice, some
> question it because, they say, the role of cryptography in protecting
> privacy has been overblown.
>
> "If you think cryptography is the answer to your problem, then you
> don't know what your problem is," said Dr. Peter G. Neumann, a
> computer scientist at SRI International in Menlo Park, Calif.
>
> Dr. Neumann explained that there are always ways to get around
> cryptography barriers and that these methods have nothing to do with
> breaking codes.
>
> "It's like the voting machines," he said. "You'd like to have some
> integrity in the electoral process and now folks are coming out of the
> woodwork saying, `We have this perfect algorithm for privacy and
> security.' "
>
> But, he said, while the systems may use cryptography to make sure that
> when someone touches a screen to vote, that vote is transmitted with
> perfect security, who's to ensure the integrity of the person who
> programs the computer?
>
> "There is no guarantee that your vote actually goes into the computer
> the way it looks on the touch screen," Dr. Neumann said. "What does it
> take to buy a computer programmer? A couple of years' salary and a
> house in the Cayman Islands?"
>
> Bruce Schneier, who is founder and chief technical officer for
> Counterpane Internet Security in San Jose, said that, as a scientist,
> he liked the idea of a provably secure system. "Research like this
> should be encouraged," he said. "But research is different from
> engineering."
>
> But in the real world, a burglar confronted by an impenetrable lock on
> the front door may well go round to the back and just smash a window.
> "I'm a cryptographer by trade," Mr. Schneier said. "And a provably
> secure cryptosystem doesn't do me any good. We're putting a stake in
> the ground and hoping the enemy runs into it and now we're arguing
> about whether it should be one mile tall or two miles tall. It doesn't
> matter. The enemy will walk around it," he added.
>
> Dr. Robert Morris, a retired cryptographer who was chief scientist for
> the National Security Agency, the nation's code-making and code-
> breaking agency, also questioned the primacy of cryptography.
>
> "As far as I can see, he seems to be correct - it's a provably secure
> method," Dr. Morris said. "But does that mean no one can read it?
> Nah."
>
> He explained: "You can still get the message, but maybe not by
> cryptanalysis. If you're in this business, you go after a reasonably
> cheap, reliable method. It may be one of the three B's: burglary,
> bribery or blackmail. Those are right up there along with
> cryptanalysis in their importance."
>
> Dr. Rabin said that just because there are other weaknesses in
> communications systems, that did not mean that secure encryption was
> not important.
>
> It is as though medical researchers started arguing that there is no
> need to find a cure for AIDS, Dr. Rabin said. After all, many more
> people die of heart disease, and if you cure people of AIDS, heart
> disease can still strike them.
>
> "This is not a reason not to work on H.I.V.," Dr. Rabin said. "The
> problem of H.I.V. is still important."
>
> Dr. Morris said that even though the actual breaking of codes might
> not be necessary to read encrypted messages, Dr. Rabin's method could
> have an effect. "In a sense, what it does is shift the emphasis from
> cryptanalysis to some other sort of attack," he said.
>
>
>
------------------------------
From: [EMAIL PROTECTED] (Nuno Souto)
Subject: Re: The Key Vanishes: Scientist Outlines Unbreakable Code, Read it and Weep
Boys
Date: Thu, 22 Feb 2001 12:33:10 GMT
On Thu, 22 Feb 2001 11:54:54 -0000, "Randoman"
<[EMAIL PROTECTED]> wrote:
>I think I'm missing something.
>
>How do sender and received ensure that they are synchronised so that they
>each use the same portion of the random stream as keys?
>
>If there's some kind of synchronisation signal, what's to stop an
>eavesdropper intercepting the sync. signal and logging the random stream at
>the same time?
>
If I understood correctly, the sender and receiver negotiate using
"standard" encryption for the time when they need to sync. Then they
do, separately and at each end: the sender encrypts using the "stream"
at that time, the receiver captures the "stream" to make sure it can
de-crypt.
The idea being that by the time a "baddie" had the initial negotiation
cracked, there would be so much "stream" in the middle as to make it
virtually impossible to store it all and go back to de-crypt the
message.
If so, what about random delays between the time the negotiation took
place and the transmission actually happened? That would seem to me
the only way of ensuring that someone wouldn't store the whole
"stream" between start of negotiation and end of transmission.
Cheers
Nuno Souto
[EMAIL PROTECTED]
http://www.users.bigpond.net.au/the_Den/index.html
------------------------------
From: [EMAIL PROTECTED] (John Savard)
Subject: Re: What does tempest stand for.
Date: Thu, 22 Feb 2001 13:13:18 GMT
On Thu, 22 Feb 2001 06:36:06 +0000 (UTC), [EMAIL PROTECTED] (Mark
Healey) wrote, in part:
>I know that "tempest" is an acronym (really T.E.M.P.E.S.T.) but I
>forgot what it stands for. Surprisingly this isn't in any of the
>online sources I could find.
>From what I've seen, TEMPEST was merely a code name. However, in one
place, I had seen someone turn it into an acronym...
a paper quoted on
http://www.hot.ee/nuhk/tempest.html
claims it is "an acronym for Transient Electromagnetic Pulse Emanation
Standard", but the page itself states that it is (officially claimed
to be) a codename and not an acronym;
but that isn't the one I'm thinking of. However, that page is a good
source.
The current term is an abbreviation: EMSEC, for Emissions Security.
John Savard
http://home.ecn.ab.ca/~jsavard/crypto.htm
------------------------------
Subject: Re: The Key Vanishes: Scientist Outlines Unbreakable Code, Read it and Weep
Boys
From: [EMAIL PROTECTED] (Charles Blair)
Date: Thu, 22 Feb 2001 13:54:31 GMT
I'm a little puzzled about the way the selection rule works.
Do the sender and receiver agree to a subsequence of the random stream
which they will use for their messages. E.g., take one bit at 1:00,
two bits at 2:00, one bit at 4:00, etc.
OR is it that they wait for certain patterns to show up in the stream.
E. g.: take the next bit after 5 consecutive 1's appear in the stream.
Then wait for 0100100 to appear and take the next bit after that, etc.
------------------------------
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