Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!apple!usc!orion.cf.uci.edu!uci-ics!honig From: honig@ics.uci.edu (David A. Honig) Newsgroups: sci.electronics Subject: Re: Electronic sweeping and debugging equiptments Message-ID: <21722@paris.ics.uci.edu> Date: 27 Aug 89 17:00:43 GMT References: <6660@stiatl.UUCP> Sender: news@paris.ics.uci.edu Reply-To: David A. Honig Organization: University of California, Irvine - Dept of ICS Lines: 38 In article <6660@stiatl.UUCP> john@stiatl.UUCP (John DeArmond) writes: >In article yj1@CUNIXA.CC.COLUMBIA.EDU (y) writes: >> >>Do you know any equiptment that can check whether the phone lines are >>monitored or the rooms are bugged? Do you know any anti-spy techniques >>in general? > >This CANNOT be done with sufficient reliability to bet your life on. >Especially when the adversary is the government that has control of the >switching equipment. Some equipment will detect direct-connect bugs. >Most will not detect inductive or capacitive coupled taps. And none >will detect taps initiated at the CO. Even scrambling won't work in >that environment. The existance of a scrambled signal would be more >than enough excuse for arrest. 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. However, make sure you change codebooks frequently enough so that if someone knew approximately what you meant, for some period of time, and recorded your ciphertext, they could not understand your coding. If done right, this will not attract the attention that a scrambled or otherwise coded signal would. >Your friends wll have to learn the same lessons learned by dissitants >elsewhere. > >John David -- David A Honig