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From: wjc@ll-vlsi (Bill Chiarchiaro)
Newsgroups: net.ham-radio
Subject: Re:  Ham Encryption
Message-ID: <860@brl-tgr.ARPA>
Date: Wed, 21-Aug-85 15:30:15 EDT
Article-I.D.: brl-tgr.860
Posted: Wed Aug 21 15:30:15 1985
Date-Received: Sun, 25-Aug-85 00:03:19 EDT
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    It wasn't too many years ago that the only digital codes allowed for
Amateur transmission were International Morse, American Morse, and Baudot.
Then the FCC allowed ASCII, and eventually AMTOR and "any digital code
above 50.0 MHz."
    I interpret those rules to have meant that before the allowance of
arbitrary digital codes, it would have been illegal to transmit raw binary
object code from your microcomputer over your packet-radio setup.  It
would have been legal, say, to transmit ASCII-coded representations of the
hexadecimal characters that made up your object code.  I believe the new
rules are intended to permit the efficient transfer of data.  After all, it
only takes 8 bits of raw binary to send 8 bits of data as opposed to 16
bits of ASCII (i.e. two hex characters represented in ASCII).  Also, the
new rules permit experimentation with techniques such as Huffmann (Huffman?)
codes for data compaction and convolutional codes for error correction.
    The FCC has given us permission to experiment with modern techniques
with the intent of increasing the usefullness and efficiency of digital
communications.  We must remember, however, that one of our rules (I don't
have the number handy) forbids us from taking steps to hide or obscure the
meaning of our transmissions.  I know that there may be little chance of
ever being charged with a violation of this rule as a result of your use of
data encryption, although the probability might be about the same as for
those fellows who get caught running 10 kW.  The point is, if the FCC asks
why it can't make heads or tails of your transmission, you better be able
to hand them a paper explaining how your technique furthers the efficiency
of Amateur communications.  If you don't have a good answer, you may end up
reading about yourself in the Happenings column in QST.

Bill
N1CPK