December 2003 - cypherpunks-legacy

Re: PGP 2.6 FAQ
by nobody＠kaiwan.com 17 Dec '03

17 Dec '03

tim werner(a)mc.ab.com wrote: >Stoopid question: is the above-mentioned LaMacchia any relation to the >LaMacchia who got busted for running the illicit fsp site? Yes; it's his brother.

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Re: Pedophiles in Cyberspace
by mpd＠netcom.com 17 Dec '03

17 Dec '03

Duncan Frissell <frissell(a)panix.com> writes: > The WSJ op ed page today has an article on the 1st > Amendment in Cyberspace by Stephen Bates that focusses > (analytically) on pedophiles and Usenet. It is not > hysterically negative but discusses the "downside" of our > technology. Just what the world needs. Another reporter who spends a short time on Usenet and emerges to proclaim to the clueless masses that the Internet is bursting at the seams with child porn GIFs and that the pedophiles are frolicking uncontrollably. While it would be difficult to list all the inaccuracies and misstatements of fact contained in Steven Bates' WSJ article in a single message, the following leap out at even the most inexperienced Internet user. The newsgroup, alt.sex.pedophile.mike-labbe, originally formed to discuss the legal problems of a BBS Sysop, is almost dead and averages no more than a few posts a week. While pictures are occasionally posted, they are almost without exception art taken from legal sources. While some messages have been posted which might seem to solicit illegal activity, such messages are regularly flamed by other readers of the group, and illegal activity is discouraged. Calling this group "alt.sex.pedophile" and characterizing it as the Internet's official distribution point for illegal child porn is a gross misrepresentation of reality. The newsgroup, alt.sex.intergen, formed to discuss issues surrounding intergenerational relationships, including those between adults and minors, is represented as a place where pedophiles congregate to plot their evil deeds. But discussion of the sexual rights of minors is only one issue covered under the alt.sex.intergen charter and it would be ludicrous to suggest that pedophiles are the only people to whom such issues are important. You don't have to be a member of a sexual minority to find fault with American sex and censorship laws, and such issues are discussed by people representing all ages, sexual orientations, and professions. Taking a few lurid-sounding quotes out of context from many months of postings does little to correctly convey the tone of this newsgroup. Mr. Bates repeats the popular myth that Europe is some bastion of readily available child porn easily accessed via the Internet. This is simply not the case. All the European and Scandinavian countries now have laws against distributing such material with severe penalities for violations. With the large number of American net.cops trolling the Internet looking for illegal pornography and the cooperation of foreign law enforcement agencies in shutting down sites, no such operation could stay in business for long. The comparison the article makes between "advocating pedophilia" and Holocaust Revisionism should be equally offensive to Jews and non-Jews alike. Suggesting that teenagers should have the right to choose their own sexual partners cannot be compared to denying the deliberate killing of six million men, women, and children. Dr. Fred Berlin, who should have known better, is quoted in the article as suggesting that people in general, and pedophiles in particular, are prone to do in real life everything they contemplate in fantasy. Since the world of fantasy is largely devoid of the moral and social inhibitions which constrain our real-world behavior, this is unlikely to be the case. Since Dr. Berlin is the world's foremost authority on the treatment of paraphilias, we should give him the benefit of the doubt and assume he was either quoted out of context, or like Ken Udut, deliberately misled as to the purpose for which his comments were being solicited. -- Mike Duvos $ PGP 2.6 Public Key available $ mpd(a)netcom.com $ via Finger. $

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Re: New MacPGP
by catalyst-remailer＠netcom.com 17 Dec '03

17 Dec '03

Eric writ, >I deleted it. Enough said. BTW, BinHexed files are pure ascii. -=GuEsS WhO=-

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Re: CEB 5 - The Hangover
by gtoal＠an-teallach.com 17 Dec '03

17 Dec '03

: For someone who professes to want to "beat the State", Mr. Jeffers seems to : have a lot of personal energy invested in trying to get people to do what : he says... Well, if he *really really* wants it that much, and the only thing stopping him is lack of expertise, then I'll do the work for him for two hundred dollars a day. (That's my cheap rate for fill-in work while I'm idle, which I may well be in a couple of months time...) G

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what I can say...
by perry＠imsi.com 17 Dec '03

17 Dec '03

Having seen Matt's paper, and having been asked by him not to distribute it, I feel somewhat obligated not to give any details. The complete method can actually be determined from the newspaper article (which was astonishingly lucid, all things considered) but having been "mentally contaminated" its not ethical for me to describe it. However, I'll say this. 1) He found a beautiful little defect -- it can be explained in a couple of lines, and it seems obvious, but somehow no one but Matt saw it. Its a classic -- he deserves lots of kudos. It permits full interoperability between a "rogue" Tessera user and a non-rogue user. 2) Its likely that a redesign of the EES (escrowed encryption standard) could avoid this defect. Whether it could avoid all defects is, of course, unknowable -- but the current design is simply flawed and does not truly achieve its stated goal. 3) If the NSA actually worked for years designing this thing, someone wasn't thinking. Perry

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Re: what I can say...
by Graham Toal 17 Dec '03

17 Dec '03

From: "Perry E. Metzger" <perry(a)imsi.com> 3) If the NSA actually worked for years designing this thing, someone wasn't thinking. I still maintain that the FOIA'd docs extracted by gnu imply that there's a *real* backdoor as well as the key escrow, and I suspect the key escrow/ Law Enforcement Abuse Field stuff was hurriedly tacked on as an afterthought. Personally I wouldn't rely on clipper ever *with* a private session key. G

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Re: CEB 5 - The Hangover
by jim＠bilbo.suite.com 17 Dec '03

17 Dec '03

>>It looked more like someone saying "Hey! Let's have rabbit for >>dinner! Now, you there, go kill us a rabbit. And you, over there, >>start a fire. And you..." I realize that you think that you brought >>a rabbit home, but others seem to think that you only brought a menu. > >No, Mr. Jeffers is _too_ _busy_ debugging his TSR to bring a menu. He Come on, cut the guy some slack! He fucked up and got suitably flamed. There's no need to pile it on. Jim_Miller(a)suite.com

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Re: News Flash: Clipper Bug?
by wcs＠anchor.ho.att.com 17 Dec '03

17 Dec '03

gtoal writes: > One thing this shows, even if the application of the technique turns out > to be too difficult to be practical, is that Dorothy Denning's evaluation > of the design was worthless. That team should have found this themselves. > No wonder she was trying to play it down in the NYT. Dorothy's group was highly worthwhile; you just have to understand the objectives :-) It produced a fine interim report describing how strong the strong part of the Clipper system was, making it politically easier for the NIST to declare their stuff to be a standard blessed by experts. The evaluation of the whole Clipper system, beyond just the SkipJack algorithm itself, will supposedly be in the final report, which will supposedly be out Real Soon Now, according to a conversation I had with her in March. I suspect that report is either being hastily revised (:-), or else they had already discovered it and were stalling to see if anyone else had, or they had seen Matt's draft and have already written the revisions but were waiting to see if he could get it published. On the other hand, maybe they've discovered one of the other N technical weaknesses in Clipper, or had given the system a negative review and aren't getting support from NIST to release it, or some other amusing variant. Meanwhile, way to go, Matt! Both for doing the analysis, and for getting the material to the press effectively - and also way to go John Markoff! (Out here in the San Francisco Chronicle, it only made the bottom half of Page 1 Column 1; haven't seen the San Jose Murky News yet.) Bill

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Re: LEAF forgery
by collsc＠snowbird.aud.alcatel.com 17 Dec '03

17 Dec '03

[Matt's wonderful LEAF forgery hack deleted] > Matt Blaze should be commended for finding such a big hole. As with > most such ideas, its obvious in retrospect but took some good thought > to come up with in the first place. > Indeed. Is he now working furiously on a fix for this "big hole" which he can then patent and refuse to license to Big Brother? > Let me say also that the NSA should feel highly embarassed. They > fucked up big time. My terror of them from a few days ago when we > heard the Russian Coup intercept story has lessened. Even if they are > years ahead of us, they are still human. > This is true, although difficult to remember sometimes. +--------------------------------------------------------------------------+ |Scott Collins Alcatel Network Systems| |collsc(a)aud.alcatel.com Richardson, Texas| | Even if my employers agreed with this, they would never admit it. | | GCS d? -p+ c++@ l u e- m* s+/ n- h+ f? g-(+++) w+@ t-- r- y? | +--------------------------------------------------------------------------+

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Matt Blaze's Clipper attack -- details
by smb＠research.att.com 17 Dec '03

17 Dec '03

I spoke with Matt Blaze; he gave me permission to post a summary of his attacks. But the paper is not yet available for ftp. Matt's work was done using a prototype Tessera card, with a SCSI-PCMCIA interface on a Sun 4. That may (or may not) have implications for some of the performance numbers. There are two classes of ways to foil key escrow. The less interesting class of attacks are non-interoperable. That is, two rogue implementations can talk security, but can't talk to a conforming key escrow device. But there's another attack possible, wherein a rogue application talks to a conforming device, but without presenting a valid LEAF. The LEAF contains a 32 bit unit id, an 80-bit session key encrypted with the per-device secret key, and a 16 bit checksum. The whole thing is encrypted with the family key. The checksum field is based on both the session key and the IV. A receiving device will not decrypt unless it's handed a valid LEAF. But it can only base its judgment on the checksum and on its external knowledge of the key and IV; the actual key in the LEAF is encrypted in a way that it cannot read. LEAFs are sent out of band by the application; they're not concealed in the encrypted data stream. Non-interopable applications work by generating a LEAF/IV pair and not transmitting it. (Users cannot control the IV; the Tessera interface (and maybe the Capstone chip) generates it.) The receiving end does the same thing. You don't need an IV for ECB mode, so you have at least some access to Skipjack that way. But that's too slow; at least in the configuration tested, it took ~50 ms to do an ECB encryption. In CBC mode, if you have the wrong IV, the first block of plaintext will be garbled. But the error recovery properties of CBC guarantee that all subsequent blocks will be decrypted correctly. (Derivation is left as an exercise for the reader.) The solution, then, is simple: just pad your messages with an 8-byte garbage header. OFB and CFB modes can be implemented as well. The obvious way is via ECB mode, but that's too slow. It turns out that with a bit of work, you can use CBC mode as a primitive to build OFB and CFB. I'll describe that if anyone's really interested. The more interesting attack on key escrow is a rogue implementation that can interoperate with a conforming one. The checksum is only 16 bits; it's possible to brute-force it. That is, generate random 128-bit strings, and see if your own Tessera card will accept it as a valid LEAF. Again, recall that it knows only the unencrypted key and the IV. On average, you'll find a hit in 2^15 tries; at 50 ms per try, that's 28 minutes. You can speed this up by running in parallel with multiple Tessera cards. --Steve Bellovin

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