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Physics of Computation Seminar, Monday July 19
by poc＠im.lcs.mit.edu 15 Jul '93

15 Jul '93

MIT PHYSICS OF COMPUTATION SEMINAR Date: Monday, July 19 Time: 11AM Room: 4-270 Quantum versus Classical Information: a Fruitful Dichotomy Charles H. Bennett IBM Research, Yorktown Heights Abstract: Classical information (the kind in newspapers) and quantum information (carried by certain states of elementary particles such as photons) are very different. Classical information can be read, copied, and transcribed into any medium, but it cannot be sent faster than the speed of light. Quantum information cannot be read or copied without disturbing it, but in some instances can propagate instantaneously or even backward in time. Together the two kinds of information can perform several feats that neither could do alone. These include quantum cryptographic systems, some of which have already been built, in which privacy of communications is guaranteed by the uncertainty principle; and a new technique, "quantum teleportation", by which an unknown quantum state (eg a photon of unknown polarization), can be dismembered into purely classical and purely nonclassical parts, transmitted through separate channels to a new location, and recombined there to produce a perfect reincarnation of the original state. Host: Norm Margolus, MIT Lab for Computer Science This talk is part of a new seminar series on adapting computers and computations to the constraints of, and opportunities afforded by, microphysics; and on the development and application of the physical theory of computation and information. Please forward this notice to anyone who you think might be interested. Anyone who wishes to be added to the distribution list for these seminar announcements should send email to "poc(a)im.lcs.mit.edu". This series is being sponsored by the MIT Information Mechanics Group (Lab for Computer Science), in conjunction with the MIT Physics and Media Group (Media Lab), the MIT Porous Flow Project (Earth, Atmospheric and Planetary Sciences), and the Mathematical Sciences Research Group at Thinking Machines Corporation.

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xor data hiding?
by J. Michael Diehl 15 Jul '93

15 Jul '93

I heard something interesting which made me think. (gasp) I heard that if you encrypt a file with the xor encryption alg. multiple times with different keys, you get an encrypted file with a coorisponding effective key which has some interesting properties. The key in such a system would have a length equal to the Least Common Multiple of the lengths of the original key. So, if you used keys of length 1,2,3,5,7,11,13, you would have an effective key-length of 30,030 bytes! Of course, you could use more than one 5-byte key if you wanted, and some of the bytes should be greater than 127. Not knowing any better, it occurs to me that given a 30,030 byte key, and the task of finding the original keys that make it up, (if any) I'd be out of luck. It would seem that "factoring" this large key into smaller keys would be a tough job...perhapse almost as hard as the factoring problem in a finite group? Brute-force and known plaintext attacks are possible, but lets forget that for (just) a moment. If someone DID find the required 30,030 bytes required to read your massage, you could just as easily show them another 30,030 bytes which would decode the message into the U.S. Bill of Rights if you wanted to. You could keep such One Time Pads laying around your hard disk if you wanted to...in zip format, perhapse. You would always be able to get the true plaintext by simply knowing the 7 key-words. But few others would be so lucky. The point being that there would be some degree of plausible deniability with such a cypher. For the sake of arguement, lets say that the plaintext was first encrypted with some strong crypto. Then we used the xor crypto with 7 keys. It would be pretty hard to see what had been done. Now we deal with the brute force attack to get the original keys. Lets say that someone does get 7 words which will decrypt your ciphertext into a plot to distribute <your favorite scum> to <your favorite victim>? If you had to, I'm sure you could reverse engineer a completely different set of keys which will form the same plaintext. If you absolutely had to, you might be able to come up with 7 words which will decrypt your ciphertext back into the Bill of Rights, thus giving you absolute plausible deniability. As far as known plaintext attacks go...well, we hope that doesn't happen. ;^) Well, I'm about to wrap this up. Some time ago, I proposed hiding messages on the end of other files such as executable. Well, if we pgp encrypted a file, then xor encrypted the result with 7 keys and stuck that on the end of 4dos.com, which is over 64K BTW, I find it hard to believe that you would be caught readily. I haven't had time to investigate the harmonic qualities of such a cypher, but it seems feasible. You could delete and wipe the encryption program from your harddisk. (after uploading the source/executable to your local bbs) There would be tough times for anyone who had to pin a given message on you. Well, what do you think? I hope to drum up as much discussion here as with the "radical paranoia" thread, from which I learned a lot. Well, I promised to wrap this up, so I guess I'm done. +-----------------------+-----------------------------+---------+ | J. Michael Diehl ;-) | I thought I was wrong once. | PGP KEY | | mdiehl(a)triton.unm.edu | But, I was mistaken. |available| | mike.diehl(a)fido.org | | Ask Me! | | (505) 299-2282 +-----------------------------+---------+ | | +------"I'm just looking for the opportunity to be -------------+ | Politically Incorrect!" <Me> | +-----If codes are outlawed, only criminals wil have codes.-----+ +----Is Big Brother in your phone? If you don't know, ask me---+

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unsub (request-cypherpunks not working)
by ggoebel＠sun1.ruf.uni-freiburg.de 15 Jul '93

15 Jul '93

Please unsubscribe me. I am leaving this node Saturday. for one month, mail from this list will be thrown to /dev/null, thereafter if will bounce back to the list. I have tried the request address... I have writen Eric PLEASE UNSUBSCRIBE ME... Garrett -- C. Garrett Goebel <ggoebel(a)sun1.ruf.uni-freiburg.de>

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Re: mail failed, returnin
by M..Stirner＠f28.n125.z1.FIDONET.ORG 15 Jul '93

15 Jul '93

>What's going on? There has been no mail from cypherpunks(a)toad.com for >well over a week at this site. Mail to cypherpunks bounces showing Uu> There is substantial daily volume on cypherpunks. Maybe some Uu> machine on the way... Presumably, this is the case, though why mail is bouncing from so many places all of a sudden when sent from all over the country, I can't say. I was able to get pings back from penet today after having mail there bounce. I was writing in response to a complaint from another user in the midwest who could no longer get mail to run through penet. . Charcoal's still not working. . Mail has stopped bouncing at cypherpunks(a)toad.com apparently, though the site that receives cypherpunks for me has been getting nothing for over two weeks. Seems I can send, but that's it. . <sigh!> ********************************************************************* * <m..stirner(a)f28.n125.z1.fidonet.org> - PGP Key D30909 via servers * * > What country can preserve its liberties if its rulers are not <* * > warned from time to time that their people preserve the spirit <* * > of resistance? Let them take arms!" - Thomas Jefferson, 1787 <* ********************************************************************* ___ Blue Wave/QWK v2.12 -- M. Stirner - via FidoNet node 1:125/1 UUCP: ...!uunet!kumr!shelter!28!M..Stirner INTERNET: M..Stirner(a)f28.n125.z1.FIDONET.ORG

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Clip the Clipper Consortium
by L. Detweiler 15 Jul '93

15 Jul '93

This is an AP news release on the industry rumblings we've been hearing about. Novell, AT&T, Citicorp, Hughes Aircraft, Motorola? European Community? British Ministry of Defense? ye gads! (Does GCHQ know about this? Maybe they're not into jumping off bridges like their friend NSA.) [anonymous `White House' Clipper sympathizer] > ``I think this won't drive us crazy,'' the official said. >``We'll look at this and evaluate it on its technical merits.'' hee, hee. Sounds like a hardware engineer in a competing cryptography company. These people simultaneously reside in the U.S. government and Fantasy Land. (Don't you just love that `we're giving this thorough evaluation' phrase? with Clipper it was `hm, what can we actually get away with?' here it's a euphemism for `what the hell are we going to do?') The 64k question of course: what's the CCC algorithm? p.s. if anyone could pass on the Markoff NYT article on the same please post it. ===cut=here=== Group To Set Rules For Computer Encoding< NEW YORK (AP) _ Novell Inc., the leader in network software for corporate computer systems, is set to reveal plans for protecting information stored in computers or transmitted over networks, according to a published report. Novell, leading an international industry group, was to make the announcement in New York on Wednesday, The New York Times reported Tuesday. The announcement was seen as an indirect challenge to the Clinton Administration's effort to impose a national encoding standard for computer and telephone communications, the newspaper said. The other companies involved are AT&T, Computer Associates, Citicorp, Hughes Aircraft, Motorola and smaller firms specializing in data security. Representatives from the European Community standard setting committee and the British Ministry of Defense were also to participate in the announcement. Computer and communications companies, as well as corporate users of information technology, are worried about the government's plan, which would enable it to use wiretaps with a court's authorization, the newspaper said. But an unidentified White House official told the Times that the administration could live with the move. ``I think this won't drive us crazy,'' the official said. ``We'll look at this and evaluate it on its technical merits.'' The government can influence the use of communications encoding standards by controlling what types of hardware and software that companies can export, but it has no legal means of imposing its own standard or of blocking the development of an industry standard.

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reaction to Infoworld NIST/NSA queries
by L. Detweiler 15 Jul '93

15 Jul '93

This is very interesting information, because it is extremely current and represents the first direct reactions by the behind-the-scenes authorities on some crucial aspects of Clipper and its scalding reception. > It should also be understood that the use of products > implementing the key escrow encryption microcircuit is > voluntary. There has been no attempt to either mandate its use > or to deny the entry of other encryption technologies into the > marketplace. Note in the answer to `has acrimony lessened the government commitment' the feeble whimpering ultimately falls back on the aspect that it is voluntary. Ah, the last refuge of these scoundrels! If there are any plans to restrict or limit domestic cryptography, the policy-makers (and I use the term loosely) are painting themselves into a corner. If the only redeeming feature of Clipper is that it is voluntary, then anything less is wholly unredeeming! But again, the text conspicuously does not rule out that option. > Finally, the system will be designed to ensure that law > enforcement destroys the keys it receives when its authority > to conduct the electronic surveillance has expired. Correct me if I'm wrong, but this is the first time I've seen any official indication of this requirement to `destroy keys after surveillance' -- this *is* clearly an extremely serious weakness with the scheme, and I don't use past tense there because this lip service doesn't remedy it in the least. However, we can take consolation: it appears there have been direct responses to the criticisms of the key escrow aspects. In fact, they appear to have the key-escrow issues thought out to the least (hence my very uneasy suspicions), were surprised by the focused critical analysis, and have been consistently attempting to strengthen the `baroque activities in a vault' (as one esteemed cypherpunk put it). The attempts look a little bit like desperate scramblings to me. They still don't have a clue on the escrow agencies! > Should a broader export policy be adopted, we > believe products implementing the key escrow technology will > find favor among consumers who desire the superb encryption > security offered. `superb'? hee, hee. First claim of security outside of the `superior to many other schemes on the market' weasel quote in the announcement. This sounds like vintage Sternlight. >Q. If Clipper would be the standard, would the use of non-Clipper > encryption devices be outlawed? If so, how would you find out > who was using these non-Clipper devices? > >A. No. Use of key-escrowed products by the private sector would > be entirely voluntary. here they appear to be directly suggesting that they will *not* attempt domestic cryptographic restriction. (?) > Federal agencies will have the option > of using this technology once it becomes a Federal Information > Processing Standard. This little FIPS thing (Federal Information Processing Standard) is clearly very important to all the Clipper conspirators right now (Bidzos is plugging it too, and it was in the PKP-NSA-DSA patent agreement announcement). Is there some way to sabotage the FIPS process? Cypherpunks, this is a critical window. >A. NIST will recommend that DES be renewed for another five years > as a Federal Information Processing Standard. wow, I don't recall seeing that before. >A. Again, we must emphasize that use of this technology is > voluntary. Software containing other cryptosystems is still > available to consumers. they plug the `voluntary' bit so much here you'd think they're talking about Bush's Thousand Points of Light. >A. We expect the key escrow microcircuits will be enhanced to keep > pace with future data requirements. hee, hee. They can't even keep up with *current* requirements. The chips last for an astonishingly durable 2 days. (Actually, with Clipper this is a very attractive feature!) > That does not mean, however, that a government-imposed > security policy is appropriate. Government must be actively > involved in setting computer security standards for its own > use and making its technology, expertise and guidance > available to the private sector when requested and > appropriate. wow. At first I thought this was a typo and the statement was supposed to be `does not mean it is *in*appropriate'. `when requested and appropriate'? Good lord, is this the NSA talking or did they have the day off? Maybe they actually understand they have no domestic legal regulatory standing whatsoever.

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Relation between number theory and cryptography
by hfinney＠shell.portal.com 15 Jul '93

15 Jul '93

Clark Reynard, <clark(a)metal.psu.edu>, asks about information and cryptography. As I see it, a cyphertext has at most the same information as the sum of the original message, the key, and the encryption algorithm. Without knowing the key a cyphertext may appear random, but actually it is not. If it is the encryption of a lower-information plaintext (such as English text) then it still basically possesses that low level of information, it's just not obvious how to compress it. It's not unusual for different compression algorithms to achieve very different levels of compression. In a sense, these different algorithms disagree about the amount of information in the original data. We discussed digitized speech here some time back. Ordinary compression algorithms such as Lempel- Ziv or Huffman encoding don't compress digitized speech much at all. Special algorithms such as linear predictive coding can achieve great compression. In the same way, there is no contradiction between the fact that an encrypted file looks random and incompressible, and the fact that knowing the key it becomes clear that the file actually can be compressed. Any calculation of the information content of a file can only be considered an upper bound. A more clever algorithm may always exist which will reveal the data to have much less information than was originally thought. This is basically the situation you have when faced with an encrypted file for which you don't have the key. Hal Finney hfinney(a)shell.portal.com

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Mail failed, returning to
by M..Stirner＠f28.n125.z1.FIDONET.ORG 15 Jul '93

15 Jul '93

Uu> * Reply to msg originally in u_privacy AS> Is the anonymous server in Finland (anon(a)anon.penet.fi) down for good? Uu> We shall see. There may be monkey business afoot. Charcoal is also Uu> down. We'll see if this message goes through. Mail to Penet did indeed bounce. What's going on? There has been no mail from cypherpunks(a)toad.com for well over a week at this site. Mail to cypherpunks bounces showing insane routing. Charcoal is down. Penet is down. Most cypherpunks remailers are down. What's going on? Did the cypherpunks piece on The Hightower Report finally get Deadly Attention? Anyone? ********************************************************************* * <m..stirner(a)f28.n125.z1.fidonet.org> - PGP Key D30909 via servers * * > What country can preserve its liberties if its rulers are not <* * > warned from time to time that their people preserve the spirit <* * > of resistance? Let them take arms!" - Thomas Jefferson, 1787 <* ********************************************************************* ___ Blue Wave/QWK v2.12 -- M. Stirner - via FidoNet node 1:125/1 UUCP: ...!uunet!kumr!shelter!28!M..Stirner INTERNET: M..Stirner(a)f28.n125.z1.FIDONET.ORG

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Re: The right to be secure (fwd Computerworld article)
by wcs＠anchor.ho.att.com 15 Jul '93

15 Jul '93

Paul Ferguson sent out a copy of a ComputerWorld article "The right to be secure" (ComputerWorld, Volume 27, Number 28, July 12, 1993, page 28, James Daly), which had NIST/NSA Q&A on Clipper. A couple things were mildly interesting (assertion that use of escrow products would be voluntary (if we can trust them)), but one was complex and nasty: To obtain the key needed to unlock the encryption, law enforcement must present evidence of its authority for a key, typically a court order, to both key escrow authorities. ^^^^^^^^^^^^^^^^^^^^^^^^ Finally, the system will be designed to ensure that law enforcement destroys the keys it receives when its authority to conduct the electronic surveillance has expired. "Typically", of course, means "not always", and it's coupled with the phrase "establishment of procedures by the attorney general for the access of the keys" in a previous answer, which means that anything the attorney general wants, he can get. It also suggests that keys *can* be kept longer than court orders permit if the attorney general wants. Bill Stewart

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Re: PGP
by peter honeyman 15 Jul '93

15 Jul '93

my advice is to obtain a copy of pgp, play with it, and read the docs. the sci.crypt faq is also valuable. peter

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