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From: karn@petrus.UUCP (Phil R. Karn)
Newsgroups: net.ham-radio
Subject: Re: Ham Radio and Computer Networking
Message-ID: <477@petrus.UUCP>
Date: Thu, 22-Aug-85 13:48:14 EDT
Article-I.D.: petrus.477
Posted: Thu Aug 22 13:48:14 1985
Date-Received: Sat, 24-Aug-85 16:33:29 EDT
References: <312@harvard.ARPA> <168@bunny.UUCP>
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Organization: Bell Communications Research, Inc
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> "The transmission by radio of messages in codes or ciphers in domestic
> and international communications to or between amateur stations is
> prohibited. All communications regardless of type of emissions employed
> shall be in plain language except that generally recongnized
> abreviations established by regulation or custom and usage are
> permissible as are any other abreviations or signals where the intent is
> not to obscure the meaning but only to facilitate communications."

There has been considerable discussion on the topic of authentication vs
encryption in the amateur service. So far, the consensus is that the FCC
doesn't prohibit the use of codes as long as they are for the purpose of
authenticating the sender and not for the purposes of hiding what he's
saying.  A precedent: touch tone codes for repeater control and so forth.
(There is a special exception that allows encryption on amateur satellite
control links, but that doesn't apply here.)

Paul Newland, AD7I, presented a paper suggesting several possible schemes
in this year's ARRL Computer Networking Conference. The basic idea is to
calculate some function over a packet, encrypt it and send it along with
the packet (which would be in plain text). Any modification or forgery
of the packet would likely cause the encrypted check number not to match.
You might think of this as a "checksum" or "CRC" function whose intent
is to protect against intentional corruption by an intelligent human
instead of random corruption by natural processes like noise.

Phil