July 1993 - cypherpunks-legacy

RE: Radical Paranoia?
by Paul Goggin 12 Jul '93

12 Jul '93

>Lets say someone emails me a key and the return address matches that of >the address in the key. Do I assume no one is spoofing me? You have to >admit that this is possible albeit unlikely. What good is key certification >if it only "probably valid?" I've noticed that many of the keys on the >server are signed with the same person's key. I doubt that these people >have had physical contact with each of the people who's key that they've >signed. Am I just being paranoid, or is there a valid issue here? I >welcome any of your comments. I understand your precaution and problem very well. I have had similar fears. Recently, I was in similar situation recently. I wanted to exchange keys with someone I have met only once. The situation as it arose actually ended up working okay. We exchanged keys after encrypting them with the normal encryption option, with a password being someone at the place we meet. Knowledge common to only a few select people. Then we started a talk session at a prescribed time at the relevant addresses and tried to rely on information specific dialogue to verify one's person as the one in question. Without physically being there this seems like at least a little extra security. As to the broader question you are really asking on verification I am unsure on how it can be solved. Obviously my situation was unique that we had met and could decide on an information basis, that would seemingly be hard to duplicate, but this is not always available. Paul -- R O All Comments Copyright by | Technofetisht A N Paul S. Goggin (1993) | Cypher, Cyber, Chaos V Information Broker | Ergoflux, Interzone E chaos(a)aql.gatech.edu | Carpe Diem: Stop the Clipper wiretap chip Finger account for latest _Phrack_ | Public Key: PGP and RIPEM available For anonymous communication:---> anonymus+4744(a)charcoal.com ------------------------------------------------------------------------------ Title 18 USC 2511 and 18 USC 2703 Protected -- Monitoring Absolutely Forbidden

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Radical Paranoia?
by J. Michael Diehl 12 Jul '93

12 Jul '93

I'm having a philisophical problem reguarding when to sign someone else's public key. Obviously, if you watch someone generate a key, and they physicaly hand you a copy of it, you should sign it. Fortunately, life has been this good to me about 5 times. But what if life isn't so good? Lets say someone emails me a key and the return address matches that of the address in the key. Do I assume no one is spoofing me? You have to admit that this is possible albeit unlikely. What good is key certification if it only "probably valid?" I've noticed that many of the keys on the server are signed with the same person's key. I doubt that these people have had physical contact with each of the people who's key that they've signed. Am I just being paranoid, or is there a valid issue here? I welcome any of your comments. +-----------------------+-----------------------------+---------+ | J. Michael Diehl ;-) | I thought I was wrong once. | PGP KEY | | mdiehl(a)triton.unm.edu | But, I was mistaken. |available| | mike.diehl(a)fido.org | | Ask Me! | | (505) 299-2282 +-----------------------------+---------+ | | +------"I'm just looking for the opportunity to be -------------+ | Politically Incorrect!" <Me> | +-----If codes are outlawed, only criminals wil have codes.-----+ +----Is Big Brother in your phone? If you don't know, ask me---+

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REMAILER: really anon?
by wmo＠rebma.rebma.mn.org 12 Jul '93

12 Jul '93

-----BEGIN PGP SIGNED MESSAGE----- > > 9: remailer(a)rebma.mn.org (this reply took almost 3+ days!) > > From: nobody(a)rebma.rebma.mn.org > Remailed-By: Mr. Nobody <remailer(a)rebma.mn.org> A little background on my remailer... My machine is connected to the net at large via UUCP... And I only have one phone line at home, which me and the family share with the computer. So it only polls out for mail when we're asleep (22:30 CDT - 7:30 CDT). And, I'll admit, when the weather gets ugly enough here in Minnesota, the machine gets powered down to keep the place cooler. That's the disadvantage of the remailer at rebma. The advantage is that since I own the machine, the remailer will stay in operation, period. (I think my service provider does have a clause in the agreement that mentions that use that prevents other users from getting service will not be tolerated, but that's it.) So, if you're looking for fast turnaround time, remailer(a)rebma.mn.org is not for you. If a long delay can be used as an advantage, more power to you. - -Bill -----BEGIN PGP SIGNATURE----- Version: 2.2 iQCVAgUBLD8NHRiQVHeOVJ+HAQF5AwP9HmELtb3xCOo79cxT5UpBdIiM8mJmT0D0 Fiacai6jxzZxGeq6mSgco96IgR8V3M57EJ66788v8I+vwPsuKoRS7ESgKyF7ijqn b1AfCEgh3VJfEUmPFg3Ulmg6LtDCQ5EkYEFcrhdKHqa9edvm3xVFexodKwOPDzhL tbTkxzdyiIk= =cPEm -----END PGP SIGNATURE-----

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PINE
by me 12 Jul '93

12 Jul '93

One of the many neat features of PINE is that it allows one to talk to the SMTP server _directly_, bypassing sendmail (and its security checks). What this means is that instead of doing a "telnet xxxx smtp", you can build and configure a PINE client to do it for you, and retain all the nice features. PINE source code is freely available, and does not require root privs to run (any more than it requires root privs to "telnet xxx smtp"). The pine executable does take up a Meg and a half though, which could be a problem for folks without a lot of space to play with. Coming down the pike though, I see SMTP, maybe even NNTP protocols being secured (check out the magazine someone mentioned earlier: INFO-SECURITY. You just have to fill out a bingo card to get it, Write:INFO-SECURITY NEWS 498 Concord St, Framingham MA 01701-2357). If that happens, the days of EZ phreaking are over.....

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Re: Secure comm program, Sockets + LINK
by jpp＠markv.com 11 Jul '93

11 Jul '93

From: Timothy Newsham <newsham(a)wiliki.eng.hawaii.edu> I assume you're talking about the link program I wrote. Yes, I was talking about your program Link. If so: I never really considered the RSA exchange as authentication although it can be thought of that way I guess. Right. The only person who can participate (on one side) of the exchange is the one with the private key which matches the other side's public key. This does provide a weak level of authentication. (An opponent can record 'authentication' sequences, and replay them later. For this to be usefull, the opponent will have to have discovered the session key which is/was being selected by the sequence.) If (when) I implement DH key exchange I guess I should add some sort of authentication. I was concidering a different authentication, and secret session key selection protocol (the one that got away :>). It would only use RSA (or any other suitable public key system) to sign and check signatures, as well as encrypt and decrypt data. No new number theory. However, it would require both parties to know the public key of the other. This sort of protocol would be ideal for logins. Both parties authenticate the other, and no-one else can read the channel. No passwords are ever transmitted over the channel either. You and I use a "sum" (xor perhaps?) of our two key halves as the session key. At any time one of us can simultaneously request changeing the sesion key, and chalange the identity of the other. To do this, I send you a new key half encrypted under your public key. You respond with a signature of the resulting session key encrypted under my public key. We then start using the new sesion key. At this point both directions are authenticated, and observers can't determin the new sesion key. Things are complicated a little by the fact that all comunication is done under a secret session key. Things also become a bit more complex because there may be data you sent before recieving my key change request. j'

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Re: encrypted email software
by Timothy Newsham 11 Jul '93

11 Jul '93

> > > DES isnt secure? And where was it that you got this precious > > little piece of information? > > > You mean to tell me you believe what your government tells you about DES? > Come on now! It's been public knowledge for quite some time that the NSA > has a backdoor to DES and the FBI and other agencys know it. Its public knowledge? were's the proof? Not one academic researcher has found it (and lived to publish about it). On the other hand some very respectable cryptographers have been able to show that the design critereon has made for very well chosen parameters. The FBI has shown that they dont know a backdoor in DES or at least they wont use it against suspects. There have been cases were data was encrypted with DES and the suspect refused to turn over the keys. > > I certainly hope you were kidding! > > -- > Bob Tannen > Borland International > 1800 Greenhills Rd. > Scotts Valley, CA. 95066 > > rtannen(a)borland.com > RTANNEN @ BORLAND (MHS) >

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PGPcompose, a mail wrapper
by nate＠VIS.ColoState.EDU 11 Jul '93

11 Jul '93

-----BEGIN PGP SIGNED MESSAGE----- CypherPunks, I have been looking for a good mailer lately, or at least a mail wrapper to sign and encrypt my mail easily. I was not completely satisfied with the wrappers that I could find, and especially since they mostly need perl. So, in a fit of frustration, I did what any good CypherPunk would do: I wrote one. It is called "PGPcompose" and if you invoke it with a username, it will prompt for the subject, open vi for editing, then ask you if you want to sign the message, and encrypt it (either, or both), then it asks for the key to use for encryption (if you choose to encrypt the message). It will then ask if you want to send, edit, or abort the message. it uses /usr/ucb/mail instead of sendmail, since I could not figure out how to parse the ~/.mailrc file, and since it took less than a few hours to hack out. Anyway, here it is, it's free, so do whatever you want with it. - ---------------------BEGIN PGPcompose------------------- /* "PGPcompose" (comp) -- a replacement for the mail composition */ /* program. It allows for PGP signatures and encryption */ /* for mail. It asks for the ID of who the file is to be */ /* encrypted for... I did this because I have lots of */ /* public keys, and some of the other mailers became */ /* confused on occation and did not find the right key to */ /* use for the encryption. It also asks if you want to continue, */ /* abort or edit the message... */ /* */ /* This software is free for the taking... if you modify it, send */ /* me the modification, since I'll be curious. */ /* -nate sammons, July 11, 1993, nate(a)vis.colostate.edu */ #include <stdio.h> main(int argc, char *argv[]) { int intPID; int signMess, cryptMess; char subject[130]; char cryptWho[100]; char charPID[10]; char theChoice[5]; char messageName[100]; char messageHeaderName[100]; char messageCypherName[100]; char commandLine[300]; char scriptName[100]; FILE *tmp; FILE *script; FILE *message; intPID = getpid(); tmp = fopen("/tmp/PID.tmp", "w"); fclose(tmp); tmp = fopen("/tmp/PID.tmp", "a"); fprintf(tmp, "%d", intPID); fclose(tmp); tmp = fopen("/tmp/PID.tmp", "r"); fscanf(tmp, "%s", charPID); fclose(tmp); strcpy(messageName, "/tmp/message.tmp."); strcat(messageName, charPID); strcpy(messageCypherName, "/tmp/message.cypher."); strcat(messageCypherName, charPID); strcpy(scriptName, "/tmp/message.script."); strcat(scriptName, charPID); message = fopen(messageName, "w"); switch(argc) { case 2: printf("PGPcompose, (c)1993 Nate Sammons\n"); printf("Subject: "); gets(subject); editIt: strcpy(commandLine, "vi "); strcat(commandLine, messageName); system(commandLine); signIt: printf("Sign this message? [y,n] : "); gets(theChoice); switch(theChoice[0]) { case 'y': case 'Y': signMess = 1; break; case 'n': case 'N': signMess = 0; break; default: goto signIt; break; } cryptIt: printf("Encrypt this message? [y,n] : "); gets(theChoice); cypherWithWho: switch(theChoice[0]) { case 'y': case 'Y': printf(" With whose key? : "); gets(cryptWho); if (cryptWho[1] == NULL) { goto cypherWithWho; } cryptMess = 1; break; case 'n': case 'N': cryptMess = 0; break; default: goto cryptIt; } Continue: printf("send, abort, edit? : "); gets(theChoice); switch(theChoice[0]) { case 's': case 'S': goto sendIt; case 'a': case 'A': system("/bin/rm -rf /tmp/message*"); system("/bin/rm -rf /tmp/PID.tmp"); exit(0); case 'e': case 'E': goto editIt; default: goto Continue; } sendIt: if((signMess == 1) && (cryptMess == 1)) { script = fopen(scriptName, "w"); fprintf(script, "cat %s | pgp -feast +clearsig=on \"%s\" > %s\n", messageName, cryptWho, messageCypherName); fclose(script); strcpy(commandLine, "chmod +x "); strcat(commandLine, scriptName); system(commandLine); system(scriptName); script = fopen(scriptName, "w"); fprintf(script, "cat %s | /usr/ucb/mail -s \"%s\" %s", messageCypherName, subject, argv[1]); fclose(script); system(commandLine); system(scriptName); } if((signMess == 1) && (cryptMess == 0)) { script = fopen(scriptName, "w"); fprintf(script, "cat %s | pgp -fast +clearsig=on > %s\n", messageName, messageCypherName); fclose(script); strcpy(commandLine, "chmod +x "); strcat(commandLine, scriptName); system(commandLine); system(scriptName); script = fopen(scriptName, "w"); fprintf(script, "cat %s | /usr/ucb/mail -s \"%s\" %s", messageCypherName, subject, argv[1]); fclose(script); system(commandLine); system(scriptName); } if((signMess == 0) && (cryptMess == 1)) { script = fopen(scriptName, "w"); fprintf(script, "cat %s | pgp -fea \"%s\" > %s\n", messageName, cryptWho, messageCypherName); fclose(script); strcpy(commandLine, "chmod +x "); strcat(commandLine, scriptName); system(commandLine); system(scriptName); script = fopen(scriptName, "w"); fprintf(script, "cat %s | /usr/ucb/mail -s \"%s\" %s", messageCypherName, subject, argv[1]); fclose(script); system(commandLine); system(scriptName); } if((signMess == 0) && (cryptMess == 0)) { script = fopen(scriptName, "w"); fprintf(script, "cat %s | /usr/ucb/mail -s \"%s\" %s", messageName, subject, argv[1]); fclose(script); strcpy(commandLine, "chmod +x "); strcat(commandLine, scriptName); system(commandLine); system(scriptName); } system("/bin/rm -rf /tmp/message*"); system("/bin/rm -rf /tmp/PID.tmp"); break; default: printf("Useage: comp username\n"); exit(0); } } - ---------------------END PGPcompose--------------------- - -nate sammons +-------------------------------------------------------------------- | Nate Sammons email: nate(a)VIS.ColoState.Edu | Colorado State University Computer Visualization Laboratory | Finger me at nate(a)monet.VIS.ColoState.Edu for my PGP key | #include <std.disclaimer> | "I have but one single desire - to tear down the sky" -A. Toomba +----------------------+ -----BEGIN PGP SIGNATURE----- Version: 2.3 iQCVAgUBLECF4NTgi1fmrpxlAQGhbgP6AiZCyU2+qf5O06r3mE1JB4XWDocuK175 CO/HJU/8+QekgBG7+6PewERnqLt0pVPuTVmdWkHJyQ+VJyrPRiDlWzI7G2yJqwvG sTCI9CT6cHbp0jBRzQhj48SFcN+Gr+nZ06Nc8/93X7/+QGZVtz+0MMTFXz8oVcEe TWYeBNkXhDg= =P0IW -----END PGP SIGNATURE-----

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No Subject
by akcs.brendan＠vpnet.chi.il.us 11 Jul '93

11 Jul '93

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Re: Secure comm program, Sockets + LINK
by jim＠tadpole.com 11 Jul '93

11 Jul '93

> Supose you opened up a socket on the local machine. And that you > ran your usual telnet to connect to it. The program listening on the > local socket would be responsible for running one end of a 'LINK' like > secure protocol. It would connect to either the remote telnet socket, > or a special purpose socket at the remote end. There either you can > use a pipe to a pty (standard telnet -> login shell -> LINK -> pty), > or in a special socket through LINK out the telnet socket. (There is > an obvious extention with multiple hops through LINK-socket programs > which should provide the same kind of anonymity that is provided by > the CP remailers.) This is the kind of thing which is just perfect for a streams-based tty/networking environment. Create a streams module that implements Link and DH key excng. Push it on your tty stream at both ends. Works over modems, telnet/rlogin, what-have-you. A similar module could be created to sit below the IP module in SVRx-based Un*xes. > It is also likely to be obsoleted as soon as secure-ip gets out. And once the vendors for both endpoints update to it. Could be a while. > Infact it would be nice to see some socket (perhaps 32?) become the > standard for the secure telnet service. I think it would be much better to develop something that will work with the current port numbers, else we stand a good chance of asking for a 'new' secure port foreach well-known service. (Secure SMTP, Secure ftp-cmd, secure ftp-data,...) Jim

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Re: REMAILER: really anon?
by Carlos Macedo Gomes 11 Jul '93

11 Jul '93

> If you can trace the origin (sender) of this message please send me mail > personally rather than to the list. I'm using my favorite remailer here > and I want to make sure it's working right. [stuff deleted] > My main curiosity in this quest is to determine what each header will look > like when the mail is recieved. I think this is important in determining > which remailer to use. [stuff deleted] > Thanks! > -z > **Please take note of remailer 12 of this list.** 12: remail(a)tamsun.tamu.edu > From: remail(a)tamsun.tamu.edu > Remailed-By: Anonymous <remail(a)tamsun.tamu.edu> > > Received: by tamsun.tamu.edu id AA04104 > (5.65b/IDA-1.4.3 for you@yourhost); Tue, 6 Jul 93 04:15:57 -0500 > > you@yourhost = your address! ...really! > > 13: remail(a)tamaix.tamu.edu > > From: remail(a)tamsun.tamu.edu > Remailed-By: Anonymous <remail(a)tamsun.tamu.edu> The remailed email from tamsun and tamaix have the same format, but you have interpreted the headers incorrectly. Please note that you@yourhost mentioned above is not the sender's address but rather the recipients address. You might have been confused by this if you were sending and reading from the same account. The mail from tamsun and tamaix IS anonymous. Take a look at this piece of the header for your message to the cypherpunks list: Received: by tamsun.tamu.edu id AA24627 (5.65b/IDA-1.4.3 for cypherpunks(a)toad.com) Fri, 9 Jul 93 16:21:06 -0500 As you can see you@yourhost as you demarked in your message actually refers to the recepient's address and not the sender's. If I have misunderstood your message, please excuse. I just felt compelled to clear any doubts about the anonymity of these two remailers. Please feel free to reply to me personally if you'd like to get a close look at the remailers. ciao, Carlos -- [ Carlos Macedo Gomes ][ Quis Costodiet ][: .8. :]------ [ gomes(a)tamu.edu ][ Ipsos Custodes? ][ . ooo . ]000000 [ cmghelp(a)tamsun.tamu.edu ][ ----------- ][ : =o(Y)o= : ]000000 [ PGP 2.2 key by finger ][30 37 40 N, 96 20 03 W][oo .ooooo. oo]------

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