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lucas encryption beta available
by markh＠wimsey.bc.ca 29 May '93

29 May '93

U.S. and Canadian cypherpunks: I have a very early BETA of a free program that uses LUC and triple DES available. (uses gmp-1.3, only runs on Unix-like systems) I'm making it available in the hope that people will grab it, look it over and send comments, criticisms &c. anon ftp to netcom.netcom.com cd /pub/henderso get lucas-0.3.4.tar.z (gzip format) it binary mode. If you need gmp, you can also find it in the same directory. Please don't export this outside of the U.S. and Canada. -- Mark Henderson markh(a)wimsey.bc.ca (personal account) RIPEM key available by key server/finger/E-mail MD5OfPublicKey: F1F5F0C3984CBEAF3889ADAFA2437433

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Trust, Amateur/Professional, use of PRNGs
by meyer 29 May '93

29 May '93

>Date: Thu, 27 May 1993 11:33:06 -0400 >From: "Perry E. Metzger" <lehman.com!pmetzger(a)cactus.org> > >meyer says: >> >> Perry Metzger writes: >> >> >Correct me if I'm wrong, but from what I understand, "Dolphin Encrypt" >> >does not use any well examined crypto system -- its something that you >> >guys, without any cryptography credentials, cooked up. On that basis, >> >why should we care about it? Most crypto systems that amateurs come up >> >with are pathetic to say the least, and strong systems, like >> >triple-DES and IDEA, are widely available. >> >> So far the DE method has not been well-examined, except by its >> developers (who have spent years on this). > >In that case, I do not think it is worthy of trust. (See "The >Codebreakers" by David Kahn for dozens upon dozens of stories of >amateurs who spent long times producing cryptosystems that were >essentially junk.) I am not asking that you take it on trust. If I were I wouldn't be revealing the details of the encryption method and I wouldn't be subjecting the software to critical examination. You omit to point out that Kahn also discusses the cryptosystem invented in the late 18th Century by Thomas Jefferson. I'm not aware that Jefferson was a "professional" cryptologist or that he was "credentialed" in this field. Yet his cryptosystem was sufficiently strong that even after 1922 "other branches of the American government used the Jefferson system, generally slightly modified, and it often defeated the best efforts of the 20th-century cryptanalysts who tried to break it down! To this day the Navy uses it." (Kahn, p.195 of the hardbound edition.) This shows that your distinction between "professionals" (by implication, the experts) and "amateurs" (by implication, the self-deluding fools) is false. There is no such clear-cut distinction. Whether a cryptosystem is strong or not has to be decided by an examination of the system itself, not on the basis of whether its author has attended cryptology classes at M.I.T. >> Statistical tests have not revealed any patterns in DE-encrypted >> ciphertext so far. > >Or in 99% of other crypto systems. I can construct completely trivial >and easily broken crypto systems that don't reveal any patterns >without careful analysis. As an example, it takes mere minutes to >break a cryptosystem constructed by XORing the plaintext stream with >the output of a linear congruential pseudorandom number generator -- >but the output will indeed look random to ordinary statistical tests. XORing the plaintext with the outcome of a linear congruential PRNG is a very simple-minded way to use a PRNG. Such operations are certainly amenable to mathematical analysis. No doubt you've read your Abraham Sinkov on "Mathematical Cryptanalysis" and other such works, where the solving of simultaneous equations in several (perhaps many) unknowns may yield a solution in some cases. Yet I fail to understand why you assume that someone (even someone "uncredentialed") who uses PRNGs in a cryptosystem will necessarily do so in a simple-minded way. I can't imagine why any intelligent designer of a cryptosystem would commit that error.

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Reply to Eric
by meyer 29 May '93

29 May '93

Eric Hughes writes: >>It has also been examined by four cryptologists (professional and/or >>credentialed) not involved in its development, and it was ridiculed >>by none of them. > >I hear the sounds of autonecrothaphty (digging one's own grave). Was >it recommended by any of them, and did any of the test it? It's true I'm going out on a limb here, but the potential benefit to the world is a new cryptosystem of some value (a deliberately modest claim). And one that was not designed by NSA complete with trapdoors. Anything new always meets with resistance. The description was run by the cryptanalysts for their comment. The consensus was that the method was probably strong, or at least not obviously weak, but that they had insufficient information to judge properly. You may disagree. You may not like the proposed method, but the real question is whether it works. In-house testing has been as rigorous as we can make it, but any outside cryptanalyst is welcome to take a shot at it. >>The first task of a cryptanalyst >>is to discover what method of encryption was used. > >Usually not. This often comes as collateral information related to >the intercept. In the case of a PC seizure, having a manual lying >around and an executable on the disk usually qualifies. Yes, a cryptanalyst looks around for other evidence as to which cryptosystem was used before the hard work of analysing ciphertext. As you say, it may be a manual or an exmcttable. The encipherer himself may reveal it. But in any case, identifying the encryption method *is* the first step in cryptanalysis.

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Modified Vigenere encryption?
by poier＠sfu.ca 29 May '93

29 May '93

-----BEGIN PGP SIGNED MESSAGE----- I was just thinking... What if one were to use Vigenere encryption with a key at least as long as the message (therefore making the incidence of coincidences irrelevant)? A key made of, for instance, words strung together from a dictonary selected pseudorandomly? Are there other weaknesses in the Vigenere system that are escaping me? Perhaps one could use (in the pseudorand words example) distribution / transition / equilibrium proabilities in the english language? If so, are there any other options for generating a long key without the need for a truly random key (which would make using the Vigenere table pointless because it would just be an one- time-pad)? Also, what are the weaknesses of the Playfair cypher? My texts mention it, but don't say much of anything other than how it works... Just pondering at odd hours... Skye - -- - -----====> Skye Merlin Poier <====----- Undergrad in CMPT/MATH (Virtual Reality) |||| |||| email: poier(a)sfu.ca p-OO <--> OO-q THINK PGP Public Key available on finger \== ==/ -----BEGIN PGP SIGNATURE----- Version: 2.2 iQCVAgUBLAXAvS0bkpXW3omvAQG5EQP/dVH9mxGEvd59ec5e63LKvq45QCwW3K/W QQU9KlkqGsqw6s5R9N3JQeK+BEIDhq2qViPkP9PPDBPmK9nyAx1zLxQ7tP5W+HvT wuFeG+Yqzg5IBsOQXRKPaBeNJcgCyDXUgFSKSRT0fGD1n5XCb7zKScht2p4Cp0CB 07jUWV0cPqQ= =Cydq -----END PGP SIGNATURE-----

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Data Insecurity Packages, etc.
by meyer 29 May '93

29 May '93

Clark Reynard writes: >Indeed. There were a pair of papers in Cryptologia a few years ago >on ``Data Insecurity'' packages. The author cryptanalyzed a number >of different PC-based crypto packages, and contrasted that with >the glowing advertising copy... This may or may not be one of those papers: Martin Kochanski: "A Survey of Data Insecurity Packages" in Deavours et al., Cryptology, pp. 195 - 209. None of the encryption methods analyzed by Kochanski were particularly complex, even though it did take skill to crack most of them. It turns out that in each case the encryption algorithm used is fairly easy to state (in, say, half a page). Perry Metzger writes: >Correct me if I'm wrong, but from what I understand, "Dolphin Encrypt" >does not use any well examined crypto system -- its something that you >guys, without any cryptography credentials, cooked up. On that basis, >why should we care about it? Most crypto systems that amateurs come up >with are pathetic to say the least, and strong systems, like >triple-DES and IDEA, are widely available. So far the DE method has not been well-examined, except by its developers (who have spent years on this). I took a step toward public examination of the method by posting the natural language description here on cypherpunks a few weeks ago. (Anyone who missed it can get it from me.) This description has been available in the manual for a year now, for anyone who cared to purchase the product. It has also been examined by four cryptologists (professional and/or credentialed) not involved in its development, and it was ridiculed by none of them. As I said, the complete details are in the C code, which is available at present to anyone who purchases the library, and which will be made public sometime down the road. Of course, any crypto system must be made available to public examination before it can be judged strong or otherwise. If I didn't think the DE encryption method was strong I wouldn't be making it public. Just because we have DES and IDEA doesn't mean we should be satisfied with them only. The first task of a cryptanalyst is to discover what method of encryption was used. If that is known (and solving this problem itself may be non-trivial) then cryptanalysis may proceed either by (i) a study of patterns in the ciphertext or (ii) a thorough study of the encryption method used. Statistical tests have not revealed any patterns in DE-encrypted ciphertext so far. We'll see whether analysis of the DE method by others reveals any flaws. Until then I'm reminded of the saying: "Those who can, do; those who can't, criticise." This brings up an interesting question: what charactersistics, if any, do different encryption methods produce in ciphertext? From a study of several large samples of ciphertext produced by a particular encryption method, what clues might there be to the identity of the encryption method used? I'd like to hear if anyone knows of any published work which addresses this question. Since DES in electronic code book mode (which is considered insecure) encrypts 8-byte chunks which are independent of each other, it's entirely possible that the ciphertext can be identified as the product of DES-ECB.

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Oh, da horrah.
by fergp＠sytex.com 29 May '93

29 May '93

-----BEGIN PGP SIGNED MESSAGE----- On Thu, 27 May 93 23:04:21 -0600, ""L. Detweiler"" <uunet!longs.lance.colostate.edu!ld231782> wrote - > Apparently someone has forged a Sternlight posting on sci.crypt and > alt.privacy.clipper. If the author can hear me: you should be severely > ashamed. I've said before that Sternlight is actually (in a warped way) > a *resource* to the net because of his representation of the NSA and > `fuzzy-brained public' opinion. Without him, we'd have nothing but all > of ourselves in a bland choir. > Cypherpunks, maybe we can help track down the culprit. The forgery says > `recently, some have called me a dupe'. Perhaps it is an allusion to a > recent flame war wherein the counterfeiter participated. > Cypherpunks are sneaky, but not sleazy. I look forward to the day when > digital signatures and other authentication methods make forged > postings like this a strange historical anachronism. I'm surprised no one realized this before now. My first reaction to this was that of humor. My second reaction was that I felt embarrassed for thinking it was funny. My subsequent reaction was that of irony. As was overheard in the newsgroup - > From: steiner(a)jupiter.cse.utoledo.edu (Jason 'Think!' Steiner) > Date: 27 May 93 07:09:07 EST > heh. maybe David should start signing his posts with PGP so he won't > have this problem in the future. :^) > [yeah, the irony was deliberatly manufactured by whoever forged that > post, but it's still too good to pass up.] I couldn't agree more. I do, however, agree that it was a pretty sleazy trick on somone's part -- but the irony factor is just too surreal. Cheers. -----BEGIN PGP SIGNATURE----- Version: 2.2 iQCVAgUBLAYovJRLcZSdHMBNAQGLtQP/Y5mGsWAGqtCwHYpiPkq/98ofprvRowq3 AZ1u+w0TJSYXeZpF+jSr6cOLH8boWS1Ud3tugFTUuQA/SD7sMFSwdPlvBzfHAIiE 1BiVs7+SDCFOPXXpttv8PezR0ZspyXwxNofGZVM1wXLG1siPBE3XeEbBjKp2SCev DK5Ez1QbSCI= =2Pne -----END PGP SIGNATURE----- Paul Ferguson | The future is now. Network Integrator | History will tell the tale; Centreville, Virginia USA | We must endure and struggle fergp(a)sytex.com | to shape it. Stop the Wiretap (Clipper/Capstone) Chip.

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ADMIN: sequencing problems
by Eric Hughes 29 May '93

29 May '93

Many have wondered why the mail comes out of order sometimes. The following comments are my surmise of the situation; I haven't done an experimental confirmation of the situation. The sequencing problem comes from the way that toad.com handles mail. If it can't be delivered immediately upon arrival, it goes in the queue. If it can be sent out immediately, then it is sent out. Now toad.com routes to many sites through a relay at uunet; this relay bogs down. If toad.com can't connect to the relay, it queues the mail. The queue is processed only at intervals. The next mail might go out immediately, before the queue has been processed again. I see the same thing at soda. I'm not going to try to fix it. Eric

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Re: forged Sternlight posting?
by dmandl＠lehman.com 29 May '93

29 May '93

> From: ""L. Detweiler"" <ld231782(a)longs.lance.colostate.edu> > > Apparently someone has forged a Sternlight posting on sci.crypt and > alt.privacy.clipper. If the author can hear me: you should be severely > ashamed. I've said before that Sternlight is actually (in a warped way) > a *resource* to the net because of his representation of the NSA and > `fuzzy-brained public' opinion. Without him, we'd have nothing but all > of ourselves in a bland choir. > > Cypherpunks, maybe we can help track down the culprit. The forgery says > `recently, some have called me a dupe'. Perhaps it is an allusion to a > recent flame war wherein the counterfeiter participated. I think the forgery was kind of primitive and obvious (OK, I admit I did get a little chuckle out of it). But if it wasn't already clear to everyone that it was a fake, I'm sure Sternlight's and your responses made it clear. I'm strongly opposed to being cops and "tracking down the culprit." It was just an innocent joke, and no one was hurt. If Sternlight's ego was bruised, then (as my mom used to say) "my heart bleeds for him." It's not a big deal. We've got better things to do than help David Sternlight fight his battles (though I agree it's useful to have him around). --Dave.

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forged Sternlight posting?
by L. Detweiler 29 May '93

29 May '93

Apparently someone has forged a Sternlight posting on sci.crypt and alt.privacy.clipper. If the author can hear me: you should be severely ashamed. I've said before that Sternlight is actually (in a warped way) a *resource* to the net because of his representation of the NSA and `fuzzy-brained public' opinion. Without him, we'd have nothing but all of ourselves in a bland choir. Cypherpunks, maybe we can help track down the culprit. The forgery says `recently, some have called me a dupe'. Perhaps it is an allusion to a recent flame war wherein the counterfeiter participated. Cypherpunks are sneaky, but not sleazy. I look forward to the day when digital signatures and other authentication methods make forged postings like this a strange historical anachronism. ------- Forwarded Message

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CPSR Seeks Clipper Docs
by Dave Banisar 29 May '93

29 May '93

PRESS RELEASE May 28, 1993 CPSR Seeks Clipper Documents - Brings Suit Against NSA and National Security Council Washington, DC -- Computer Professionals for Social Responsibility filed suit today in federal district court seeking information about the government's controversial new cryptography proposal. The "Clipper" proposal, announced by the White House at an April 16 press conference, is based on a technology developed by the National Security Agency that would allow the government to intercept computer encoded information. Law enforcement agencies say that capability this is necessary to protect court ordered wire surveillance. But industry groups and civil liberties organizations have raised questions about the proposal. They cite the risk of abuse, the potential loss in security and privacy, costs to US firms and consumers, and the difficulties enforcing the policy. Marc Rotenberg, CPSR Washington office director, said "The Clipper plan was developed behind a veil of secrecy. It is not enough for the White House to hold a few press conferences. We need to know why the standard was developed, what alternatives were considered, and what the impact will be on privacy. " "As the proposal currently stands, Clipper looks a lot like 'desktop surveillance,'" added Rotenberg. David Sobel, CPSR Legal Counsel, said "CPSR is continuing its oversight of federal cryptography policy. These decisions are too important to made in secret, without public review by all interested parties." In previous FOIA suits, CPSR obtained records from the General Services Administration questioning the FBI's digital telephony plan, a legislative proposal to require that communications companies design wiretap capability. More recently, CPSR obtained records through the FOIA revealing the involvement of the National Security Agency in the development of unclassified technical standards in violation of federal law. CPSR is a national membership organization, based in Palo Alto, CA. Membership is open to the public. For more information about CPSR, contact CPSR, P.O. Box 717, Palo Alto, CA 9403, 415/322-3778 (tel), 415/322-3798 (fax), cpsr(a)cpsr.org

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