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From: wunder@hpcea.HP (Walter R. Underwood)
Newsgroups: net.news.adm
Subject: Re: reading of other people's mail
Message-ID: <2710003@hpcea.HP>
Date: Sun, 29-Jun-86 23:56:42 EDT
Article-I.D.: hpcea.2710003
Posted: Sun Jun 29 23:56:42 1986
Date-Received: Tue, 1-Jul-86 02:11:46 EDT
References: <21500002@hplabsc.UUCP>
Organization: HP Corporate Engineering - Palo Alto, CA
Lines: 43

> Users of the Msg and/or Elm mailer will find that this feature already IS
> implemented: the following message text will transmit an encrypted message;
> 
> --------
> this is a sample message
> [encode]
> This is the encrypted part
> [clear]
> this is back to normal.
> -------
> 					-- Dave Taylor  (taylor@hplabs.HP.COM)
> 
> ps: For reasons of portability to non-US sites, I choose to use a public
>     domain 13-key rotor encryption algorithm that I got from someone (Tw?).
>     This means that if the person at the other end is cruisin' along reading
>     your message in a mailer OTHER than Msg/Elm, you're outta luck.  Perhaps
>     if this becomes a sufficiently popular function this will change...

Dave got the rotor program from me.  It was written by Tracy Tims and
posted to net.sources as "cypher" in January 1983.  Paul Bame fixed it
to work correctly on the 68000 (byte order, I think).

Unfortunately, Dave made a small change which makes ELM's encipherment
a pain to use with the original version.  Cypher used "[cypher]", and
"[clear]".  Dave changed that to what you see above.

Why, I don't know, since a rotor machine really is a cipher and not a
code.  I suggested that he change it back, but ...

As for non-US use, both cypher and Elm call crypt(3) to munge the key.

As shipped, cypher works quite well with the BSD mail program, and
anything else that talks to an editor the same way.  Just set EDITOR to
your real editor, and VISUAL to "rcypher" (a link to cypher), and use
~v to encipher or decipher a message.  Handy.  I've used it to protect
a few messages (a job opening, a discussion about a product in the very
early stages of development).

Back to the subject:
   Has anyone written something that uses the RFC-822 header line?
   What are approved values for the field?

Walter Underwood