john@stiatl.UUCP (John DeArmond) (08/28/89)
honig@ics.uci.edu (David A. Honig) writes: >This won't work for speech but for letters and radio (and is amenable >to machine translation), >If you use a method of coding your messages where: > You use ordinary phrases to mean other things, > And you use a shared, trusted codebook ( translation lookup-table), >Then you could use unsecure channels to communicate securely. I'm sure the Chineese student organizations can easily find out all they need to know about one time pad cyphers but this is not the issue. I don't know about you but if I knew that my government was listening in on my phone conversations and I further knew that the penalty for "crimes against the state" was death, I sure as hell not take a chance with my life that the cypher would work. The fact is that when the government controls the rules, it really does not matter whether it can determine what you meant. IT only matters that the government has had its suspicions aroused enough to arrest you and present you to a firing squad. There are methods that dissitants can use to communicate in such situations. Few involve electronics of any kind and none involve a public switched network. -- John De Armond, WD4OQC | Manual? ... What manual ?!? Sales Technologies, Inc. Atlanta, GA | This is Unix, My son, You ...!gatech!stiatl!john **I am the NRA** | just GOTTA Know!!!
raoul@eplunix.UUCP (Otero) (08/28/89)
While it is true that it is theoretically impossible to detect a properly installed and designed phone tap, what government agencies have the resources? Especially in their foreign offices, to cover literally thousands of phones? (Specifically, the Chinese students here). Such installations are *expensive*, and Ma Bell does *not* like other people messing with her gear. Nor do Ma Bell's "siblings". A high impedance tap at the central office relays cannot be spotted. OK, but most taps are wire taps or inductive taps inside the building hooked to a transmitter or recorder. That means you can trace your house phone wiring to a cheap local tap. But this is all electronic games, and can be outsmarted by someone willing to put in the work and money. A more effective way to test this, based on behavior, is to make some false conversations over the suspect lines that involve whatever your suspected listener is interested in. Look for some reaction to *that*. For example, plan a meeting or message dump in an observed place. Wait for them to show up, and make sure you are absolutely clean when they grab you. I've tried this, for suspect confidants although not for government tapped phones. It has worked reasonably well for me. But if you establish that your phone or home is tapped, what in the heck do you do then? -- Nico Garcia Designs by Geniuses for use by Idiots eplunix!cirl!raoul@eddie.mit.edu
darrylo@hpnmdla.HP.COM (Darryl Okahata) (08/29/89)
In sci.electronics, honig@ics.uci.edu (David A. Honig) writes: > If you use a method of coding your messages where: > You use ordinary phrases to mean other things, > And you use a shared, trusted codebook ( translation lookup-table), > Then you could use unsecure channels to communicate securely. [ ... ] > If done right, this will not attract the attention that a scrambled or > otherwise coded signal would. In practice, it is extremely difficult to have a codebook that produces a conversation that makes sense and flows smoothly, and, if you do not have a coded message that makes sense and flows smoothly, it will stand out a like a sore thumb to trained eyes. -- Darryl Okahata darrylo%hpnmd@hpcea.HP.COM
henry@utzoo.uucp (Henry Spencer) (08/29/89)
In article <2120002@hpnmdla.HP.COM> darrylo@hpnmdla.HP.COM (Darryl Okahata) writes: >> You use ordinary phrases to mean other things, >> And you use a shared, trusted codebook ( translation lookup-table), >> Then you could use unsecure channels to communicate securely. > > In practice, it is extremely difficult to have a codebook that >produces a conversation that makes sense and flows smoothly, and, if you >do not have a coded message that makes sense and flows smoothly, it will >stand out a like a sore thumb to trained eyes. It can be done, by making the "codes" sufficiently high-level. You can use what Heinlein dubbed "idea code", in which the actual wording does not matter at all -- the meaning is encoded by the content. For example, a lament about the high cost of art supplies means "you are believed to be under suspicion" while an inquiry about Aunt Katy's health means "you are believed to be in the clear". This does make for bulky messages if you're trying to send anything complex, though. -- V7 /bin/mail source: 554 lines.| Henry Spencer at U of Toronto Zoology 1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
ken@argus.UUCP (Kenneth Ng) (08/30/89)
In article <775@eplunix.UUCP>, raoul@eplunix.UUCP (Otero) writes:
: While it is true that it is theoretically impossible to detect a properly
: installed and designed phone tap, what government agencies have the
: resources? Especially in their foreign offices, to cover literally thousands
: of phones? (Specifically, the Chinese students here). Such installations are
: *expensive*, and Ma Bell does *not* like other people messing with her gear.
: Nor do Ma Bell's "siblings".
Why bother with adding equipment? If you have access to the central
switching offices, why not use the test/troubleshooting (hm) circuits?
These circuits have alledigedly been in switching systems for years.
Kenneth Ng: Post office: NJIT - CCCC, Newark New Jersey 07102
uucp rutgers!andromeda!argus!ken
bitnet(prefered) ken@orion.bitnet
--
Kenneth Ng: Post office: NJIT - CCCC, Newark New Jersey 07102
uucp !andromeda!argus!ken *** NOT ken@bellcore.uucp ***
bitnet(prefered) ken@orion.bitnet