December 2003 - cypherpunks-legacy

Re: Explaining Zero Knowledge to your children
by danisch＠ira.uka.de 17 Dec '03

17 Dec '03

> Clever, but I think it's missing an important element of zero knowledge > interactive proof systems. For example, why not simply open _both_ hands? That's the same problem as with the cave: Why not just go into the left passage and come out of the right passage. Both are absolute proofs. If you have two identical bills you must be able to copy them. In a cryptographical proof there is always the chance to guess. The chance is sometimes 50%, sometimes very small. What about this idea: Alice is caught in a dark room somewhere on the world. She doesn't know where she is, but there is a telephone in the room and she calls Bob to ask him where she is. Bob claims to know it but doesn't want to reveal. He calls her back. When the phone is ringing, he has proven the knowledge of her phone number, but she still doesn't know where she is or how he could know. And there is still the chance that Bob has guessed the number. Mmmh, Hadmut

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Why Surveillance State Needs Toy Crypto
by tcmay＠got.net 17 Dec '03

17 Dec '03

At 8:19 AM 9/19/95, Christian Wettergren wrote: >What I don't understand is why the law-enforcement is so concerned >about bruting things. It is probably quite easy to tap the keyboard, >smart force, exchange the binary with the real thing etc for them? > >(Unless they want to read it all from a nice tipped-back armchair in >a certain location? :-)) > >What I'm saying is that this kind of attack should work quite easily >in the one-by-one cases, but not on a large scale, malicious data, >trojan horses, outright bugging. So why all this Clipper (son-of-X) >fuss? It's really about the threat model. Sure, the authorities _could_ place microphones in offices and homes, but this requires huge amounts of effort and is only justified when the target is really, really important. As Whit Diffie has said (and this makes about the fifth time I've credited him on this, so I hope he's satisfied), widespread surveillance must attack the communication channels, not just attack the origins and destinations. That is, the _economics_ of mandating weak crypto are vastly more efficient for the surveillance state. --Tim May ---------:---------:---------:---------:---------:---------:---------:---- Timothy C. May | Crypto Anarchy: encryption, digital money, tcmay(a)got.net 408-728-0152 | anonymous networks, digital pseudonyms, zero Corralitos, CA | knowledge, reputations, information markets, Higher Power: 2^756839 | black markets, collapse of governments. "National borders are just speed bumps on the information superhighway."

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Re: Verification of Random Number Generators
by Andrew Loewenstern 17 Dec '03

17 Dec '03

> Just an idle thought: it might be possible to do a probabalistic > verification of a RNG by sampling it over some number of samples, > and statistically analyzing the sample space. This would be analysis > under the model of "RNG as black box" as opposed to (or rather, if > you're smart, in addition to) code inspection & review. Any > statisticians among us? But this wouldn't have solved Netscape's problem. Netscape was using a pretty good PRNG (the one in RSAREF). The problem was they were/are using a naive method of seeding it. The output of the PRNG would have been statistically random, but since the seed had ridiculously little entropy it was easy to guess. andrew

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Re: "Hackers"-- brief review and anecdote...
by Steve Bryan 17 Dec '03

17 Dec '03

At 8:36 pm 9/16/95, Steven Levy wrote: >>I saw "Hackers" yesterday. It's not bad and its political sensibility is >>very cyberpunk. The ad campaign even uses the tag line, "Their only crime >>is curiosity." > >It may not be a crime, but it's not nice to steal a title. I suppose this means that when "Hackers" comes out on video there's no point in looking for a cameo appeareance of the author of the identically named book?

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"Hackers"-- brief review and anecdote...
by pcw＠access.digex.net 17 Dec '03

17 Dec '03

I saw "Hackers" yesterday. It's not bad and its political sensibility is very cyberpunk. The ad campaign even uses the tag line, "Their only crime is curiosity." Given that a major studio is spending beaucoup bucks to spread this tag line, I think it is safe to say that cyber issues are very mainstream by now. Still edgy enough to be exciting to many, but definitely comprehendable. The characters are just a bit too cool for school and some of the notes ring false. The evil one, a corporate computer security officer, would have been better served by someone who is not as laughable as Fischer Stevens. I could probably hit the escape key on my computer here and he would cringe. Jeremy Irons or Klaus-Maria Brandaur would have been more inspired. But they can't skateboard. I also stopped by the Department of Motor Vehicles yesterday. The lines were long and I soon found myself grousing along with the guy behind me. He was about 60 years old and not part of the cyberpunk generation in any way. After I said some libertarian thing by wondering aloud about why we even needed to have such a huge bureaucracy centered around cars, he said, "Yeah. Have you seen all the land they have down in Fort Meade. Beautiful land and they just spend their time down their spying on the people." He lumped the NSA in with the DMV. To him, it was just one big bureaucracy. -Peter

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Re: "Hackers"-- brief review and anecdote...
by Rev. Mark Grant 17 Dec '03

17 Dec '03

On Sun, 17 Sep 1995, Brian Davis wrote: > Phill obviously presents one point of view, vigorously and well. What do > the rest of you think about a teen who, say, busts into a .edu site, > plays with the files, and ultimately brings the system down entirely for > 36 hours? Fun and games? Send him to his room, sans modem? Prosecute > him? Have a TLA hire him??? If it wasn't for ITAR the Net would already have secure encryption and authentication, and most such hacker attacks would be impossible (or at least impractical). Mark

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Re: NYT on Netscape Crack
by Andrew Loewenstern 17 Dec '03

17 Dec '03

Adam Back writes: > Posting the code for the random number generator would be an > excellent start. Ian posted the code for the PRNG on August 30th and Stephen Kapp noted that it was similar to one in RSAREF. The PRNG is probably fine. The big flaw here was the collection of seed material. The bottom line is the WHOLE security subsystem should be published for analysis. > Or if that doesn't sit well with copyright interests, how about > writing up an open spec about how the random number generator works? > Then we can critique it. Netscape did this with SSL and what happened was the rest of the industry jumped on it before any analysis was done. Now we are likely stuck with a poor protocol. > An algorithm should be something to be proud of, "it's secure, and > see: this is how it works, here are the design criteria, here is > how you would attempt to break it, and here is the best predicted > attack's cost." The design may be great, but if the implementation is flawed then you aren't much better off. To attempt to evaluate the security of a system you need to be able to inspect the implementation. Period. > is netscape still a progressive startup company with hot programmers > running the show, or has it slipped into stuffy corporate realms > already? Netscape may have hot programmers but so far I believe it has become self-evident that they know little about crypto and implementing cryptosystems. To Netscape's credit, Jeff Weinstein claims that the team implementing the security for Navigator 2.0 is completely new and of course Netscape has hired Tahir ElGamal, who certainly knows what he is doing. Additionally I would suspect that with all the bad publicity they are receiving they would take up Bidzos on RSADSI's offer to analyze the source. So it is entirely possible that Navigator 2.0 will be much better. However, I am not holding my breath. Strong crypto is _hard_ to implement properly. Even if a product is using a well-known algorithm there could be any number of subtle flaws that can destroy any security offered by such algorithm. You can't just toss in RSA, IDEA, RC-4, DES, etc... and claim the thing is secure. andrew

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Avoiding weak IDEA keys?
by danisch＠ira.uka.de 17 Dec '03

17 Dec '03

At the CRYPTO '93 there was a presentation about weak IDEA keys (page 224 of the proceedings). Does anybody know about IDEA implementations considering this and trying to avoid weak keys, e.g. by using the modified key schedule? Hadmut

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unabomber paper
by lethin＠ai.mit.edu 17 Dec '03

17 Dec '03

is available on http://www.ai.mit.edu/misc/unabomber

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Re: Verification of Random Number Generators
by droelke＠rdxsunhost.aud.alcatel.com 17 Dec '03

17 Dec '03

> > Just an idle thought: it might be possible to do a probabalistic > verification of a RNG by sampling it over some number of samples, and > statistically analyzing the sample space. This would be analysis under the > model of "RNG as black box" as opposed to (or rather, if you're smart, in > addition to) code inspection & review. Any statisticians among us? > In a word - no. In a longer description - you can black box test the *pseudo-RNG in one of two ways. One, input a key, and then keep asking for numbers. The numbers should be statistically distributed, and should have a very long repeat cycle. (i.e. basic "good" pseudo-random number generator theory) Two, input different keys, and then ask for a number. Again, the numbers should be statistically distributed, even for small changes in the input numbers. What *both* of those methods don't test, is the key(seed) generation, which is what was attacked on Netscape. The seed number must be truely random, and unknowable to the attacker, otherwise they can duplicate the random number generator. Remember that all random number generators in software are really pseudo-random number generators, and rely on having seed value. BTW: In some ways, I feel sorry for Netscape being nailed by everyone including the press like this. BUT - they must also accept that with being popular, that they will be subject to intense scrutiny. Besides - if you are going to attack a cryptosystem, why not get your 15 minutes of fame out of deal while you are at it ;-) Dan ------------------------------------------------------------------ Dan Oelke Alcatel Network Systems droelke(a)aud.alcatel.com Richardson, TX

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