December 2003 - cypherpunks-legacy

Re: Fortress Remailers
by macorp!moonlight!ken＠uu4.psi.com 17 Dec '03

17 Dec '03

Could one set up a virtual remailer that floated around a set of news groups? The active remailer would pass an encrypted token to a randomly chosen member of the set which would become the remailer for the next interval. A compromized member of the set might then eat the token, rendering th remailer inoperative, but maybe that could be overcome. Although I don't have much more than a layman's grasp of cryptography my basic thought is to consider the set of potential mailers the way one would consider some known element in a cryptographic scheme, such as a randomly accessed lookup table, so that if a cracker couldn't determine the next element in the table, she couldn't determine where the remailer would be next, either.

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Re: Anyone seen the 'quantum cryptanalysis' thread on sci.crypt?
by doug＠OpenMind.com 17 Dec '03

17 Dec '03

Tim May: >In any case, the Shor work on a quantum factorer is interesting, but >is at least several decades away, in my opinion. And even then it is >likely to be "workable" out to some number of digits (roughly, number >of digits = precision needed), by which time the conventional advances >in computer power will mean we're all using 10,000-bit moduli >(especially if we have just heard that NSA has just spend $32 billion to >build a Shor machine able to factor 3000-bit moduli :-} ). I won't argue whether Shor's work will be implemented or not within any given time period, but I thought that one of the most important properties of it is that once (and if) achieved, the resources required to factor increasingly large moduli lengths go up only polynomially, not exponentially. Doug Cutrell

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Re: 3DES
by GRABOW_GEOFFREY＠tandem.com 17 Dec '03

17 Dec '03

>Quick question. There's a brief mention in Applied Cryptography that >triple DES uses: > > Eabc(x) = Ea(Db(Ec(x))) > >as opposed to: > > Eabc(x) = Ea(Eb(Ec(x))) > >in order to preserve some symmetry properties. Can anyone give a >better explanation? I thought it goes like this: Eab(x) = Ea(Db(Ea(x))) Anyone? G.C.G. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | Geoffrey C. Grabow | "What we demand are rigidly defined | | Oyster Bay, New York | areas of doubt and uncertainty!" | | | -------------------- | | grabow_geoffrey(a)tandem.com | Clipper, SkipJack & Digital Telephony | | | JUST SAY NO!!! | |----------------------------------------------------------------------| |PGP 2.6 fingerprint = AA 9E 35 12 F8 93 72 8D 1C E5 D5 BC 74 BE 49 D3| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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Mandatory email verification
by Dr. D.C. Williams 17 Dec '03

17 Dec '03

Greetings: Is anyone aware of a way to modify sendmail to require a verified digital signature for all mail sent? This subject came up after a discussion of the possible repercussions of forged email through port 25. Even a good PGP user can't use manual encryption on a message-by- message basis as a defense for false mail attribution. For example, someone forges a defamatory message and signs your name to it. The recipient brings it to public attention and you try to claim "it doesn't have my PGP sig, therefore I didn't send it". The obvious counter is that you purposely failed to sign it to preserve your plausible deniability. The only way this would work is if the system you're on won't accept mail unless accompanied by a digital signature, which would allow the user to claim innocence if it wasn't his sig. The mailer would also have to check the sig to ensure that it belongs to an authorized user on the system to prevent people from creating one-time keys just to appease the mailer and prevent their real sig from being used. Running this version of "SIGmail" (<-- note flashy new marketing name) on your system would seem to be a reasonable defense against claims of false attribution. Has anyone done any work along these lines? Is there an obvious fault with a system which would operate in this manner? Please don't misconstrue this as an attack on anon mail, which obviously needs to be preserved. What I'm interested in avoiding is mail forged with another user's name. All that's required to do a convincing job now is an account on the user's home system and some knowledge of ESMTP. Seems to me like this is a potential disaster waiting to happen. Maybe the H.E.A.T. crew can solve this one . . . Fabio, we need you! =D.C. Williams <dcwill(a)ee.unr.edu>

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FABIO META: cartoon transcript
by sw＠smds.com 17 Dec '03

17 Dec '03

"Fox Trot," by Bill Amend, for Wed, Sept. 28, 1994: Computer: WELCOME TO COMPUNET. YOU HAVE 65,031 WAITING MESSAGES. Kid: [pause with pensive expression] Maybe setting my username to "Fabio" wasn't such a hot idea. Computer: DIANE(a)NASA.GOV WISHES TO CHAT. LUCILLE(a)OSU.EDU WISHES TO CHAT. JOYCE(a)UPS.COM WISHES TO CHAT. ... --Steve

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NYT on TLA Rot
by John Young 17 Dec '03

17 Dec '03

Today's NY Times has front page article and editorial on a congressional study to be done on the need for the CIA and reassessment of eleven other intelligence agencies. Says funds for the study were included in recent $28 billlion package for intelligence. One excerpt: "Throughout the cold war, the nation needed a great intelligence service, and by and large, it got one," said Allen Goodman, a former CIA official and dean of the School of Foreign Service at Georgetown University. "But from about 1985 onward nobody's been able to say if they are good or bad, and from 1990 onward nobody's been able to say exactly why we need them." End excerpt. Bet many "national threats" are in the offing. Email available for the NYT-impaired. John

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Digicash Palo Alto
by Hal 17 Dec '03

17 Dec '03

Just browsing www.digicash.com, I see a relatively new web page with some info on various employees. They also mentioned that there is a U.S. office, DigiCash Inc 701 Welch Road, Suite 323 Palo Alto, CA 94304 USA tel +1-415 321 0300 fax +1-415 321 0322 Bay area CP's might want to check this out (unless it is already common knowledge). (I notice Chaum has his own picture and initials on the DigiCash coins in the graphics!) Hal

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Re: Quantum Cryptography Biblio.
by chen＠intuit.com 17 Dec '03

17 Dec '03

As an addendum to the bibliography that Tim Cole posted, there are three good papers in the July 1993 edition of _Physical Review A_ (vol. 48 no. 1): "Information-theoretic limits to quantum cryptography" by Stephen M. Barnett and Simon J.D. Phoenix, "Quantum cryptography without conjugate coding" by Simon J.D. Phoenix, and "Quantum computers and intractable (NP-complete) computing problems" by Vladimir Cerny. - Mark - -- Mark Chen chen(a)netcom.com 415/329-6913 finger for PGP public key D4 99 54 2A 98 B1 48 0C CF 95 A5 B0 6E E0 1E 1D

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re: new rules: filing electronic tax returns
by Martin Minow 17 Dec '03

17 Dec '03

In an note to Cypherpunks, LaurenN(a)wri.org notes that the IRS will require fingerprints (and other information) for people filing tax returns electronically. My understanding is that this refers to professional tax preparers. Note that individuals are currently filing "electronically" by sending their return to an agency, such as the MacInTax people. The problem the IRS faced, as I understand it from a brief report on NPR, is that there was a lot of fraud going around -- people filing bogus returns with refunds, then disappearing with the money. LaurenN also wondered why CPA's and lawyers are exempt -- I would imagine that this is because their identity is known through their professional licensing. Just my speculation. Martin Minow minow(a)apple.com

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3DES
by pstemari＠bismark.cbis.com 17 Dec '03

17 Dec '03

Quick question. There's a brief mention in Applied Cryptography that triple DES uses: Eabc(x) = Ea(Db(Ec(x))) as opposed to: Eabc(x) = Ea(Eb(Ec(x))) in order to preserve some symmetry properties. Can anyone give a better explanation?

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