Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site mouton.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!mouton!karn From: karn@mouton.UUCP Newsgroups: net.ham-radio Subject: Re: Packet Radio Vax access Message-ID: <185@mouton.UUCP> Date: Fri, 19-Oct-84 21:08:45 EDT Article-I.D.: mouton.185 Posted: Fri Oct 19 21:08:45 1984 Date-Received: Sun, 21-Oct-84 14:07:50 EDT References: <2257@pur-ee.UUCP> Organization: Bell Communications Research, Inc Lines: 34 I too have been thinking a lot about using packet radio for high speed remote access to a Unix system. The problem of broadcasting your Unix password all over two meters is a real one, but there are ways the problem could be solved with public key cryptosystems. The current sentiment among the legal eagles is that such a scheme would NOT violate the prohibition against "codes and ciphers" in the amateur service because it is intended as a authentication scheme and not to hide information. There is ample precedent for authentication schemes, e.g., repeater autopatch and control codes. The regular traffic would still have to be transmitted in the clear, of course, and this would provide "spoofing" opportunities for a bad guy. It would only take one spurious packet of the form "rm -rf *" from some clown and even though the protocol might recover from the unsolicited acknowledgement, the higher-level damage would obviously be done. About the only thing that could prevent this would be a public key authentication scheme on each and every packet. Another clever (non-encryption) scheme for protecting radio communications links is in use by the military. It works on the fact that the atmosphere has widely varying attenuation with frequency, and in particular at frequencies near 60 GHz the atmosphere is virtually opaque due to oxygen absorption lines. Secure point-to-point radio systems use frequency-agile transmitters which operate as high up on this absorption curve as possible while still being received at the intended recipient. If an enemy tries to intercept the beam somewhere farther along, atmospheric noise and attenuation will make the signal useless. You're probably best off using a laser (infrared, so to not attract attention.) It has the additional advantage of not needing a license, and not being subject to the amateur rule restrictions against business use. Phil