November 1992 - cypherpunks-legacy

Remailer at rebma
by rebma!rebma!wmo＠kksys.mn.org 26 Nov '92

26 Nov '92

I've got Hal's PGP mods to the remailer code installed on rebma. The remailer is remailer(a)rebma.mn.org, and the PGP key to use is: -----BEGIN PGP PUBLIC KEY BLOCK----- Version: 2.0 mQCNAisUI2QAAAEEAKgm07Hsje5KpmXYd5azk0R6AES+qK7LcofnVGojUs7GBghD WbwrmW8oOEOhRorlShRALKeYspV4xYIw4WDkJcJxuf1B254scz1urF/Eem3zPW9b yPAx7W/cGwvs6SouZvFcSDq4v1zApvGE9hP4szPzHeGmVr0NVNeaDK0guoCpAAUR tCBSZW1haWxlciAocmVtYWlsZXJAcmVibWEubW4ub3JnKQ== =/qHx -----END PGP PUBLIC KEY BLOCK----- See Hal's previous messages for how to use the remailer, or write me, and I'll dig his messages up. I liked Fen's idea about bartering remailers. I'm all for it. -Bill -- Bill O'Hanlon wmo(a)rebma.mn.org

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No Subject
by fen＠genmagic.com 26 Nov '92

26 Nov '92

On the issue of digital cash and remailers tcmay writes: >Banks, escrow services, etc. will all have "reputations"... Note that a good reputation is good as gold. Now, when I get my remailer up and running, I'll run it for a while in "free mode" (while I get the bugs out) and then I'll put it into "reputation sharing mode" which works as follows: Every time I get a message to be re-mailed, I remember the sender's site name. Later, when I desire to mail something, I may choose to send it through that site. If operating in free mode, it passes through. If it is not a remailer or doesn't accept my message (via a bounce) I take it off my list of friendly mailers and and begin bouncing messages that it sends to me. This should, of course, all happen automagically. I realize that I am describing this somewhat poorly (it's late and I'm tired) but the basic concept is to get everuyone who wants to send mail through a re-mailer to become a remailer, or perhaps buy "friendship" with one through external means. This propogates remailers. The simplest form of barter is one for one. Fen

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Sharp Wizard as a Crypto Dongle?
by tcmay＠netcom.com 26 Nov '92

26 Nov '92

All the interesting discussion of building RS-232 crypto dongles, notably the proposal of Yanek Martinson, remind me of the idea kicking around of simply programming a Sharp Wizard (or Casio B.O.S.S., etc.) to do the same function. (And eventually much of our critical encryption will likely be done on more powerful devices like the Apple Newton, General Magic gizmo, and Eo thingamajig.) These devices have several advantages: 1. Cheap. $150 or less. 2. No construction required. 3. Not likely to have trapdoors or other limits, at least not in the hardware, or in the units you buy today at your local electronics superstore. 4. RS-232 connections for PCs, Macs, etc. (used to be as an add-on, now often bundled with the units). 5. LCD display, keypad, etc. (some of the features Yanek was envisioning in later models of his dongle). 6. A fairly slow CPU, but one which is well-integrated with the other features (and which saves us the effort of designing and debugging). 7. Some have PCMCIA capabilities. 8. They can be used for other thingss when not being used as a dongle. 9. New versions of the software (e.g., PGP 3.21) can be added more easily, I suspect, than in a custom-built RS-232 dongle. 10. It is unlikely the NSA, FBI, or Patent Office could "ban" such devices, as they are already widely deployed. Only the specific programs that make them act as crypto dongles would be "bannable," and I doubt this could be enforced. By the way, the same arguments could be applied to using cellular telephones as the base for building/programming portable, personal crypto devices. (An exciting talk at Hackers on mods to Oki 900 cellphones was an eye-opener.) I don't think an easy interface to RS-232 ports exists, but I know some cellphones interface to computers (the Oki 900 above sure did). --Tim -- .......................................................................... Timothy C. May | Crypto Anarchy: encryption, digital money, tcmay(a)netcom.com | anonymous networks, digital pseudonyms, zero 408-688-5409 | knowledge, reputations, information markets, W.A.S.T.E.: Aptos, CA | black markets, collapse of governments. Higher Power: 2^756839 | PGP Public Key: by arrangement.

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using personal organizers or palmtops for crypto
by yanek＠novavax.nova.edu 26 Nov '92

26 Nov '92

> notably the proposal of Yanek Martinson, remind me of the idea kicking > around of simply programming a Sharp Wizard (or Casio B.O.S.S., etc.) > to do the same function. I have thought of that before. Actually, I was thinking of using a notebook computer with 2 serial ports as a prototype/proof of concept. > These devices have several advantages: True. But there are also disadvantages: They generally don't have two serial ports. This may not seem like much, but is actually a serius problem. Since they tend to have small screens, weak keyboards, and not the greatest comm software, you might not like using it as your window into the cyberspace. The advantage of a standalone device with two rs232 ports is that you can continue to use your existing terminal, pc or a mac, along with all its conveniences. > 1. Cheap. $150 or less. I hope to make my device in this price range or less. I can not be sure yet because I don't have a definite hardware design completed, but that is the range I am aiming for. I don't know, maybe I am unrealistic, but I think that in kit form it could be significantly under $100. > 2. No construction required. If this idea ever takes off in a big way (about a hundred orders or so) then I have an electronics company that could build them for me. > 3. Not likely to have trapdoors or other limits, at least not in the > hardware, or in the units you buy today at your local electronics While they may not have any intentional trapdoors, since you don't have the full design specs, you can never be sure of everything that is going on within the machine. For example, if in my device I have a section of memory that holds the private key, and I clear it (overwrite with nulls) then I can be reasonably sure that if someone was to get the device they would not be able to retrieve the private key from anywhere. In a machine such as a Wizard, you never know where the number may end up, for example in some area of memory used for the auto-resume feature or some kind of cache. If a device was not designed with security in mind it is likely to be insecure. > 6. A fairly slow CPU, Might severely limit the length of keys you can handle, therefore the level of your security. > 7. Some have PCMCIA capabilities. See my previous post on why PCMCIA is not a very good choice of technology for this purpose. > 9. New versions of the software (e.g., PGP 3.21) can be added more > easily, I suspect, than in a custom-built RS-232 dongle. I plan to build it as a generic processor with two RS-232 ports. All the crypto stuff would be handled in software. So to cope with new formats, etc. all you would need to do is reprogram the EPROM. This is completely unrelated to the topic at hand, but: > By the way, the same arguments could be applied to using cellular > telephones as the base for building/programming portable, personal > crypto devices. (An exciting talk at Hackers on mods to Oki 900 > cellphones was an eye-opener.) I don't think an easy interface to > RS-232 ports exists, but I know some cellphones interface to computers > (the Oki 900 above sure did). What interfaced to the computer was the control functions (dial, signaling, etc.) It sure was fun and useful, but not nearly enough to make a secure telephone. The actual speech (that which you are trying to encrypt) is never actually digitized.... -- 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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Steve Kent on certification trust paths
by gnu 26 Nov '92

26 Nov '92

Steve is one of the key folks in the Internet PEM project. He sent this message last month during a discussion of why PEM uses top-down key certification rather than the "mesh" style that PGP uses. I hope that our (cypherpunks) experience with mesh key exchange will teach us a lot about whether and how it works. Nobody has ever tried this before, so we are doing research! John Gilmore ------- Forwarded Message Message-Id: <9210212125.AA27956(a)TIS.COM> To: Peter Williams <P.Williams(a)cs.ucl.ac.uk> Cc: pem-dev(a)TIS.COM Subject: Re: Perhaps OSI security is not possible in a liberal community! Date: Wed, 21 Oct 92 17:24:42 -0400 From: Steve Kent <kent(a)BBN.COM> Peter, You have receibved replies from a couple of folks (via pem-dev) who have expressed views on why a strictly hierarchic certification system is not required. As the author of the words you cited in raising your question, and as an advocate of a strict certification hierarchy, let me respond. It is clear that one can construct a certification system which is not a tree, but rather is a mesh. The PGP approach is an example of such a scheme and X.509 permits this. However, there are a number of advantages to a hierarchy which have motivated its use in the Internet: In a pure certification mesh, one acquires certification paths by following chins of implied trust. It is not at all obvious that this approach scales well. The PGP folks do not yet have significant experience in this regard, so it will be interesting to see how the mesh develops over time. Most folks who have spent considerable time exploring this issue believe that unbounded transitive certification, with no required name relationships, is a bad idea. The rationale is that whatever trust one might accord to an entity may not apply transitively. I may give a house key to my neighbor to be able to open my house under certain circumstances, but that does not suggest that I would give the key to whomever that neighbor provides his key. It seems difficult to characterize the nature of trust in these "lateral" arrangements and applying trust transitively is even more difficult. From a user interface standpoint, it is generally agreed that most users are not capable of evaluating a certification path. In PEM we feel that a user should know the distinguished name (or an alias assigned by the user locally) of a message originator/recipient, and some indication of the policy under which the user was certified, e.g., a short-hand name for the PCA. This is about all we expect a user to be able to deal with. The though of a user really paying attention to (much less applying meaningful value judgements to) all of the DNs in a certification path boggles the mind. I won't clain to understand all the details of what PGP provides for managing key rings. However, if one were to provide a management tool for mesh certification in general, I think it ought to permit a user to construct a trust graph expressing the relationships implied by certification paths he acquires. The user might be able to express a degree of trust and a level of allowed transitive certification for each entity in the graph. Disply of this info, to allow a user to manage the graph, would be necessary. All in all, it seems to be pretty complex and it is highly questionable if most (many?) users could make use of this facility without getting confused. But, this analysis is based on reasoned speculation, not actual experience. The naming issues is a related, but somewhat indepedent topic. DNs provide many good features for use with a certification system. One wants the names to be globally unique and manageable in a distributed fashion. Being able to express a through, rich name is important if this technology is ever to expand beyond casual use in R&D environments. Note that DNS names are not great choices. Although there are close to a million DNS host names, that represents a very small portion of the population that one wants to serve with a system like PEM. Most DNS names are very short and will eventually reuslt in collisions as more individual and organizations are registered. The problem is worst in the U.S. where we have adopted a parochial scheme with GOV, EDU, COM, ORG, and MIL at the top, vs. other countries which prefix their DNS names with a country code. What's worse is that many DNS indivdiual names are not very mnemonic and thus don't offer much in the way of indentification outside of a very narrow context. There is sometimes confusion about the role of certificates. X.509 makes it clear that they serve only for identification, not authorization. This is improtant because it is difficult enough to manage them for identification purposes without overloading authorization info on them. Also, the entities who grant authorization may often be different from those who vouch for the identity of an individual (or organization) and thus this independent is appropriate. Often there seems to be a desire to bind more info into a certificate in support of authorization, but I (and many others) believe this to be a mistake. One can construct other certificates (like the PACs EMCA has defined) to use public key technology for authorization, leveraging off of certificates used for identification. Finally, there is revocation. We have adopted both a push and a pull facility for CRLs in PEM and the PEM CRL format differs slightly from that in X.509. Many folks fail to appreciate the subtleties of CRLs at first. Hot listing on a CRL says that either a key has been compromised OR a name has changed. If we have fine-grained, organizationally-related names, then these names will change with some frequency and thus CRL entries will arise. Because a certificate establishes a binding between a name and a key, it seems appropriate that only the entity which vouches for this binding (a CA of some tyep) should be able to revoke it. That is the model we use in PEM and we add the important feature of having each CA advertise when it will issue its next CRL, so that user's know when each CRL they hold is obsolete. Peter, I hope this note helps explain the very terse words I put in the PEM key management document. Steve ------- End of Forwarded Message

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neat features that could be added to the crypto dongle
by yanek＠novavax.nova.edu 26 Nov '92

26 Nov '92

Here are some neat ideas: If you and me both had one of these devices, we could connect them, and exchange our public keys. We could also exchange other public keys on our keyrings. Another useful thing it could do: watch the incoming rs-232 traffic for anything that looks like a public key. When one is detected, you would have the option of storing it on your keyring. It could have an LCD display, and then it could calculate a hash function of someone's public key and display it. This would make it easy to verify keys by phone or any other means. Instead of spelling out the 130-character alphanumeric sequence you would only need to verify a short (maybe about 8 to 12 digits) number. As someone mentioned, if something has a keypad and an LCD display, it can also be a calculator. And, if it has two RS-232 ports it could be a break-out box or a line analyzer. But I think this is creeping featurism. -- 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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RE: PGP on local machine (was Re: MacPGP)
by DrZaphod 26 Nov '92

26 Nov '92

In Message Wed, 25 Nov 92 10:30:09 PST, Eli Brandt <jarthur.Claremont.EDU!ebrandt(a)netcomsv.netcom.com> writes: >You compose the message, using emacs or some other Turing-complete editor. >You hit the "PGPify" key [sequence]. >emacs echoes a special START string >The local comm program recognizes it and goes into "capture" mode. >emacs blats the plaintext to stdout, where it is captured. >emacs echoes a STOP string. >The comm program sees this, stops capturing, shells to DOS, and runs PGP. >emacs kills the original text block. >(emacs command ends) >The comm program shoves the cyphertext into the uploadt editor to write your messages then you've just lost the whole reason for encryption. TTFN! DrZaphod [AC/DC] / [DnA][HP] [drzaphod(a)ncselxsi.uucp] Technicolorized

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advantages of RS-232 based crypto device
by yanek＠novavax.nova.edu 26 Nov '92

26 Nov '92

A number of people responded, both privately and publicly to my RS-232 dongle idea. Several offered help with the hardware/schematics design. Some thought that PCMCIA cards would be better for this. Theoretically, yes. They could contain more memory and processing power in a smaller space. There are several problems with PCMCIA. First, not nearly as many devices have PCMCIA interface as RS232. Second, you can not make a PCMCIA card yourself, nor can you easily open it and look what's inside. My proposed design would consist of only off-the-shelf parts, the schematic would be published, so anybody could build the device for himself. I might distribute it in the kit form, which would include all the parts and the PCboard, and a case. This way, you can test each component in any way you want, and then put the thing together by yourself. Even if you got the complete unit from me, you could open it up, and look inside. You could see if it actually corresponds to the schematic. Some people doubted the possibility of its second greatest advantage, the ability to work with any computer or terminal regardless of operating system, mail software, comm software, etc. Also it could be used between an ASCII terminal and a (non-trusted) host. Here is an example of a design that I think will work with any software/host/terminal/etc combination. If I am wrong, please let me know. NOTE: this is not the final design of the device, just an example. ===================================================================== Since the device needs to have a processor anyway, it may as well have a built-in simple line-mode editor that is good enough for composing mail messages. So to use the device to send mail, you would: 1. Give the mail command to your host (or BBS) using whatever command or menu selection you normally use to send mail. Then if the mail program puts you into a mode-based editor like vi, enter insert mode (press i or a). 2. Push the "encrypt" button on the device (or send a magic sequence from your terminal). 3. Type your message in a simple BBS style (in case you have not used a BBS, this is the kind of editor they usually use: You simply type text. Every line has a number. When you press return, the next line number appears. At the beginning of a line, you can issue commands for example with a slash or a dot. commands include things like DONE, ABORT, DEL LINE, INSERT, etc.) If you had the text prepared on the local machine, you could simply transfer the text, and then type the "DONE" command. All this while, the text is only stored in the memory of the crypto device, the remote host is still waiting for input. So plaintext never crosses the line or network. 4. When you are done, the text would be encrypted (you would select a public key from the keyring, or it could be automatically determined from preceding text (such as the e-mail address). You would have the option of signing the text. The device transfers the encrypted text to the host and becomes transparent. You then type the command to tell the host that you are finished typing the message, and off it goes! ========================================================================== Now, if you see any reason why the above would not work, please let me know. A number of people wondered if the tamper-proof memory for private key storage was necessary. Some other people wondered if it was in any way effective (i.e. if someone gets the device, they can just use it to decrypt/sign stuff; so what if they don't get they actual key out of it). I tend to agree. I will have to think some more about this. It would certainly make the design much simpler (and cheaper, and consistent with the desire for off-the-shelf parts) if I avoid use of such exotic hardware. The private key may be protected from use by un-authorized users by encrypting it with a key, and requiring it to be entered on a keypad on the device. Someone suggested that the key must be typed in periodically (every x minutes). The only case I could see a problems with this approach is if "they" get you while you are using the device. For the next x minutes they can decrypt any old messages they may have stored. I believe this addresses all the concerns that have been voiced about this device. If you have any other concerns, questions, or comments, please let me know. -- 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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Re: RS232 Crypto Dongle (idea for widely accessible crypto technology)
by karn＠qualcomm.com 26 Nov '92

26 Nov '92

>Much better for this application is the PCMCIA standard, which has >plenty of room for circuitry. I had this in mind too. But there's a problem -- if we have to depend on commercial manufacturers to build these things, how will we know if we can really trust them? I'm not impugning the manufacturers themselves, as it's entirely possible that the FBI and/or NSA wouldn't even let them build and sell a device like this if it's "too" secure. That's the paradox of freely-available crypto software like PGP. The software, including source, is open for inspection by all. But because it runs on general purpose computer hardware, it's vulnerable to all of the usual computer security attacks (viruses, modifications to secretly record or transmit keys, keystroke monitors, etc). Going to small, dedicated pieces of hardware removes these vulnerabilities, but then we're right back where we started -- with an opaque piece of commercial hardware whose secure operation we can't verify. Unless, of course, we can get the technology to build PCMCIA cards ourselves out of readily available parts... Phil

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News item
by bwebster＠pages.com 26 Nov '92

26 Nov '92

Is this sudden flood of cypherpunk mail this afternoon mean we're all avoiding doing any work before taking off for Thanksgiving? ;-) AP news item in today's San Diego Union: Headline: "CIA chief hints change needed in ban on probing Americans" Excerpts: WASHINGTON--CIA Director Robert Gates says changes might be needed in the U.S. law that forbids the agency from collecting information about Americans or U.S. companies. Such changes might enable the CIA to better support the Justice Department and other law enforcement agencies, he said in an interview with the Associated Press. The idea grew out of a recent storm of accusations by Democrats in Congress, Justice Department officials and a federal judge that the CIA withheld information in the case of $5.5 billion lending scheme to Iraq by an Atlanta bank. ... [Gates said] the case of the Iraqi loans raises a broader issue of what the CIA is expected to do to aid law enforcement in such fields as financial crimes. Under current law, the CIA is strictly forbidden to collect information on Americans or American companies. "At some point it seems to me, very early on, we and Justice...and the Congress are going to have to...have some sort of serious discussion about whether there are changes in the law that are needed that will clarify some of the ambiguities and what we can and cannot do in support to law enforcement," Gates said. He did not elaborate. ... ----------------

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