- cypherpunks-legacy - lists.cpunks.org

Positive reps.
by Hal 18 Dec '92

18 Dec '92

-----BEGIN PGP SIGNED MESSAGE----- I was thinking about the idea of positive reputations and thought I'd mention a few thoughts while waiting to see Dean's notes. As I understand it, a positive reputation is basically some kind of recomendation or endorsement of a person by someone else. It might be fairly specific, like "so-and-so paid a debt of $50 to me within the agreed-upon two-week period." Or it could be more general, like "so-and-so is, in my opinion, an honest person." I was thinking of positive reputations that might be relevant to the problem mentioned of anonymous posting to mailing lists and newsgroups. As Dean mentions, we can envision a system which uses the opposite of kill files. Instead, messages would only be displayed from people who met certain criteria in terms of their reputation credentials. What would I want to see in the way of such credentials that would help me decide whether I wanted to read the message? (The issue of judging the validity of credentials is discussed below.) Maybe recommendations in favor of the poster's intelligence, knowledge, judgment, temperance (i.e. reluctance to flame), etc. would be useful. Imagine a system in which a person was rated from 1 to 10 in each of these categories. A person's positive reputation would consist of (digitally) signed statements from various "endorsers" (or "introducers"), each giving their numeric judgements about the person in question. With this system, I could set my ideal mail/news reader to only display postings from people whose scores met some standards. Maybe I would average them; maybe I would weight the different categories according to my own tastes. But this would let me filter out time-wasters like the random poster who was causing problems. Now, this still leaves open the problem of judging the validity of various credentials. This problem is very similar to the problem of accepting key signatures in PGP. If I receive a PGP key loaded with signatures, that doesn't mean much unless I know at least one of the people involved (either directly, or through the net). Only then can I judge how valid the signatures are. In the same way, if a new person posts on a newsgroup, and includes his credential loaded with 10/10/10/10's, that doesn't mean anything unless I know some of these people who are vouching for him. In the most extreme case, he could have created a bunch of false identities and had them provide all the endorsements. So an endorser unknown to me is not useful. It's interesting that the PGP key "web of trust" may have application to this more general problem. I wonder if the PEM folks will push for a centralized "email posting quality" hierarchy in which agencies rate each person's quality of postings and assign them an official score. :-) This would be the analog of their solution to the key-signature problem. That's about as far as I've gotten. A few more general comments: Such a system requires an infrastructure of public-key encryption and digital signatures. Only in that way will signed credentials be secure enough to be meaningful. Since so few people use these tools today, a positive-credential system would filter out almost everyone, throwing out the baby with the bath water. But, remailers are springing up everywhere. It is an idea whose time has come, it seems. So the problem exists today, but the solution can't be practically applied for at least another year or two, even assuming rapid acceptance of PGP, RIPEM, PEM, or some other cryptographic standard. That means that there may be some political pressure against remailers during this interval. Perhaps we can turn this to our advantage by describing the advantages of a credential system, and using that to further encourage widespread use of cryptographic programs. Hal Finney 74076.1041(a)compuserve.com -----BEGIN PGP SIGNATURE----- Version: 2.1 iQCVAgUBKzFI+KgTA69YIUw3AQEdCQP8DbPD9jrlR1MhlLOOQrSUc8Svcue2DZsj +DIXiC50bpv+C5pZYtoCa5SuOXX8W6XmZRSkZW3gilvEKDQ2Zt7hH0ol+tFnn8cs q05T1bYJIZqdMdqia6PZkVyvs+DQLuQSog5rZxAja1XfC/Rq59RnbPp2IViLqDiD OfiasXA4Egs= =GVH7 -----END PGP SIGNATURE----- Distribution: CYPHERPUNKS >INTERNET:CYPHERPUNKS@TOAD.COM

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They have to find you first!
by yanek＠novavax.nova.edu 18 Dec '92

18 Dec '92

> I would guess that all efforts towards creating secure, encrypted email > would only cause surveillance groups to focus their efforts more upon > what's showing up on your screen in plaintext before encryption and To do that, they need to know who you are and where you are located. They can't bug everyone. If a pseudonymous system is used, then it would be your top priority to make it impossible to connect your pseudonym with your legal identity. If you have not already, read Vinge's _True_Names_. If "they" know who you are and where you are located, many techniques are available, TEMPEST eavesdropping being only one of them. Others are confiscating your equipment, arresting you, threatening you and using you to track down other people. So, instead of concentrating on how to shield yourself from surveilannce once you have been found, concentrate instead on not being found. You can maintain a usual identity that you use for normal conversation, but for anything dangerous use an alternate identity, secure remailers, etc. You might want SOME shielding, in case "they" take up the practice of routinely driving up and down the streets looking to randomly find something (someone) interesting. It should be much easier to protect against a casual search. It may be nearly impossible, and/or useless to protect oneself from a determined physical attack by a resourceful enemy. It is much more profitable to prevent the attack. -- Yanek Martinson mthvax.cs.miami.edu!safe0!yanek uunet!medexam!yanek this address preferred -->> yanek(a)novavax.nova.edu <<-- this address preferred Phone (305) 765-6300 daytime FAX: (305) 765-6708 1321 N 65 Way/Hollywood (305) 963-1931 evenings (305) 981-9812 Florida, 33024-5819 (not in hiding yet :-)

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Re: TEMPEST Question
by Doug.Brightwell＠Corp.Sun.COM 18 Dec '92

18 Dec '92

>> Cpu signal is the easiest to detect, but not the only >> one. Other possible sources of emissions are all >> kinds of communications cables. Unshielded RS-232 to >> the modem, possibly even the connections to the disk >> drives. Synching up to monitor signals, I can understand. But as a non-technical person, what I'm struggling to understand is how a surveillance team could monitor the emmisions from such cables and have any clue as to what they are. Let's say they zeroed in on my poorly shielded modem cable and were able to tune into a stream of 0's and 1's. How could they then resolve that digital data into anything meaningful? It could be one of any number of documents created by one of any number of programs on one of any number of platforms. How do the spies know they're dealing with a Frame page layout document created on a Sun workstation versus a spreadsheet created on a Mac? Even if it's just a plain text file how could the surveillance team read it? Does each member of the ASCII character set have specific and identifiable radiation signatures? For example, does the letter "k" as it passes through my modem cable have a characteristic EMR that is the same for all machines? Sorry if this query is too basic, but I would appreciate any enlightenment... Doug

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abusing the system?
by UFLTAI%MEMSTVX1.bitnet＠CUNYVM.CUNY.EDU 18 Dec '92

18 Dec '92

Hiya, One of the newsgroups I was reading have this persistant "tester" who uses the anon service in Finland. Anyway, there were several different postings, all with different ids, but same kinds of "this is a test, nyah nyah" contents. As I was one of those "stop it" people, and seeing more of the same bullshit by that guy, I got slightly pissed off, and started thinking. Already that person is using about 3 different anonymous ids. If he is introduced to the remailers here, conceivably he could generate more anonymous ids for himself (ie, kill files won't work then, unless you want to kill a whole site) by routing his mail thru the remailers. Each remailer would give him another userid at that anon service. And if he uses it to loop back to the remailers... And then loop to that Australian anon service... and so on. He could "legitimately" have a hundred or so different anon_ids, from one original userid. What if someone who realises this was to use that capability to post some really "colorful" material to news? Suddenly you have a hundred or so weirdos posting "I want nude pictures of a gerbil, please" to alt.binaries. pictures.erotica... you get the idea. Is there anyway to stop this from happening? And this is on top of the real weirdos (ie, those who know how to post anonymously, like most of the readers of this list... :)) So far, the net has functioned as it's own sieve with regards to the "weirdos" but if the remailers is generally available (as it should be!), the potential for abuse is much much greater. Any way to slow it down? "Hey, look, a flame war, let's join in..." Of course, if someone was to forge a mail to the anon service... don't even need to know about the remailers... but with forged mail, the anon service can at least "check" to see the validity of your address. I realise that this is probably not important in the overall scheme of things... but I am curious about what can be done to reduce such potential abuse. Ciao. -Tai ps: Any tips on tracing anonymous mail and newspostings? I mean beyond the "from" and "path" things... ie, trace to the userid... Someone tried to forge a posting in my name... (yes, that's what got me thinking :))

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Re: Treason's bile spewing
by Richard Childers 18 Dec '92

18 Dec '92

"Treason's posts, for the past week, have been like the rantings of a third grader." This is in itself rather derogatory and does nothing to quell the flames. "I'm glad some people on this list have the resources to prove him wrong." I suspect the gentleman in question was not displeased to learn something new, and, by contributing material that _was_ a few years out of sync, he was not trying to lower the quality of the discussion ... or dominate it ... he was trying to contribute. Easy does it, folks. -- richard ===== -- richard childers rchilder(a)us.oracle.com 1 415 506 2411 oracle data center -- unix systems & network administration "If Life is a drama, then, surely, the hardest parts go to the most skillful."

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TEMPEST Question
by Doug.Brightwell＠Corp.Sun.COM 18 Dec '92

18 Dec '92

Am I correct in understanding that what's actually detected and reconstructed by TEMPEST surveillance is the EMR having to do with screen drawing, and not the CPU and other internal components involved in processing data? If that's the case, would computers without CRT-type displays still be succeptible to TEMPEST surveillance? Such as headless servers that might be running a BBS without a video card inside or a monitor. Or laptops, such as a Mac PowerBook with an active-matrix screen? Thanks, Doug

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Re: Treason's bile spewing
by DrZaphod 18 Dec '92

18 Dec '92

In Message Thu, 17 Dec 92 11:02:42 PST, netcom!tcmay(a)netcomsv.netcom.com (Timothy C. May) writes: >Our list is not moderated, that is, there is no censor or moderator >holding people back when they feel the temptation to spew bile all >over the list. With hundred of folks now on this list, great care must >be taken. > >Sorry to waste list bandwidth on this point of list etiquette. > >--Tim Well said Tim. Treason's posts, for the past week, have been like the rantings of a third grader. I'm just glad some people on this list have the resources to prove him wrong. Oh.. and what kind of prices are we talking about to, say, TEMPEST a small room.. maybe enuf for a workstation and misc. accessories. |-] TTFN! DrZaphod [AC/DC] / [DnA][HP] [drzaphod(a)ncselxsi.uucp] Technicolorized

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Patent Infringement
by Richard Childers 17 Dec '92

17 Dec '92

> This does not mean though, that it is illegal to reinvent the wheel and > apply it yourself. "I'm sorry to say that yes, it *IS* illegal to reinvent the wheel and apply it yourself. In the US it is called "Patent Infringement"." Only if you attempt to sell it ... -- richard ===== -- richard childers rchilder(a)us.oracle.com 1 415 506 2411 oracle data center -- unix systems & network administration "If Life is a drama, then, surely, the hardest parts go to the most skillful."

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enabling technologies
by yanek＠novavax.nova.edu 17 Dec '92

17 Dec '92

> I'm amazed at the progress everybody's making on so many fronts. > > --Tim What we are witnessing (and participating in) here is the synergy of enabling technologies. The availability of quality free software such as perl, and C compilers makes it easy to quickly build useful tools. These can then be combined in various ways, without re-inventing them. For example, I do not need to reinvent the strong-pseudorandom function, I can just "borrow" it from the PGP code. I do not need to write a public key system just to distribute seeds for the dc-net one-time pads system, I can use PGP. I don't need to write a program to take chunks of data and xor them together, perl has this capability. I just design a system, and put it together from existing blocks. This is the reality of what the OOP "building-blocks" people are talking about. And the important method is not object-oriented anything, but free software, with source code, and cooperation of people widely separated in time and space, some even anonymous, all linked through the nets. My dc-net system will make life easier for people that are doing digital cash, by providing a ready means of sending untraceable messages. Many useful systems can be built on top of a working digital cash system. All this is catalysed by the existence of this mailing list. For example I got the idea of reservation blocks from ILF's post of Chaum's article. That was made possible by the anonymous remailers. The anonymous remailers can be made more anonymous by linking then into a dc-net. There's a positive feedback loop developing here. -- Yanek Martinson mthvax.cs.miami.edu!safe0!yanek uunet!medexam!yanek this address preferred -->> yanek(a)novavax.nova.edu <<-- this address preferred Phone (305) 765-6300 daytime FAX: (305) 765-6708 1321 N 65 Way/Hollywood (305) 963-1931 evenings (305) 981-9812 Florida, 33024-5819

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1st dc-net works!
by yanek＠novavax.nova.edu 17 Dec '92

17 Dec '92

Finally, I got a dc-net working. It is now quite primitive, and useful only as a proof of concept. It does not yet do any key management, I just copied the binaries of several unix utilities to be used as one time pads. The reservation system does not work yet. If there is a message to be sent, it is sent immediately. That means only one of the participants can send a message in one round. The messages are not forwarded anywhere, they are just dropped to "outgoing" directory. It runs on one machine, under three accounts I created just for that purpose. The mail keeps going back and forth constantly between the three accounts, with null files being deposited to the outgoing directories. Temporary files are being created and deleted. As soon as I put a file in one of the incoming directories, within one round it appears in each of the outgoing directories. So the main function works. It is written in perl, because of the ease I can manipulate binary data of any size. As soon as I add the minimal necessary features (PGP based key exchange, and reservation blocks) I will be looking for some people to participate in an experimental dc-net. People who want to participate in this, should have fast, reliable, e-mail connections (preferably round-trip time to any other participant should be less than 10 minutes). If even one participant has a slow link, it will hold everyone up. You also need the ability to pipe incoming mail with a certain subject header through an arbitrary program. You can use any of the various 'slocal' programs, or you could use elm's filter program, or any other means. You also need to have perl working on your system. You need PGP. As someone suggested, an arbitrary group of people might not have much to talk about amongst themselves, so the next feature will be forwarding to a mailing address (or list), a newsgroup, or another dc-net. It is very simple to do the forwarding, it is a little more complicated, and interesting, to decide who will do the forwarding. I would not want to rely on any single site serving as a gateway, since that would introduce a single point of compromise. I would rather have some dynamic system, similar to the reservation blocks, that would let the net randomly decide who will forward a particular message. As soon as this first test network has run for a couple of days, and all the bugs are fixed, I will release the code, so that anybody can work on it. I expect that some people will work on various projects I mentioned in the "FUTURE ENCHANCEMENTS" section of my initial posting on this topic. I hope that people who add features to the system send the mods back to me, so I can incorporate them in a new version. When there is a number of networks running, it will be interesting to experiment with hierarchical nets, or linked networks of networks. -- Yanek Martinson mthvax.cs.miami.edu!safe0!yanek uunet!medexam!yanek this address preferred -->> yanek(a)novavax.nova.edu <<-- this address preferred Phone (305) 765-6300 daytime FAX: (305) 765-6708 1321 N 65 Way/Hollywood (305) 963-1931 evenings (305) 981-9812 Florida, 33024-5819

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