From: eric@remailer.net (Eric Hughes)
Date: Sat, 3 Dec 94 09:35:12 PST
To: cypherpunks@toad.com
Subject: Re: Disclaimer within signed body?
In-Reply-To: <199412022016.PAA16908@bb.hks.net>
Message-ID: <199412031833.KAA17387@largo.remailer.net>
MIME-Version: 1.0
Content-Type: text/plain


Todd's autosigner raises some good issues about what signatures can
actually represent.  Todd's service takes an incoming message,
attaches a note about technical means and also a signature.

As Todd points out, this signature represents the fact that a message
destined for the cypherpunks list passed through his server.  But Todd
also wants the signature to attest to the disclaimer attached to the
mail.  The signature, therefore must be affected by both segments of
text, that is, the disclaimer must be inside the signature.

There is also, however a desideratum that the original message be
preserved to the greatest degree possible.  Since two text segments
must go inside the sig block, there must be a packaging syntax to
represent a two part message composed of the original message and the
disclaimer.  There is already a syntax which accomplishes this for
email--MIME.


I'm not going to get the syntax of this example right.

-----------------------------------------------------------------------------
--- Begin signed message ---
::
Content-Type: multipart/mixed
Content-Length: [...]
Boundary: ===

Content-Type: text/ascii
===
<original message>
===
Content-Type: text/ascii disclaimer
===
<disclaimer>
===
--- Begin signature ---
a;sdfj;alsdjf;a lsjas;ldkfj;asjdf;askjdf;laskjdfdf
a;sdfj;asdjf;asfj;alsjdf;aljdf;alsdjf;alsjdf;asjdf
--- End signed message ---
-----------------------------------------------------------------------------

Now as far as aesthetics, this has got a lot of screenjunk in it.  It
does, however, represent exactly what is going on in a way that the
right kind of MIME capable reader can make exact use of.

I'm not advocating this.  I do think, though, that a minimal solution
to all the criteria at once looks a lot like this.

Eric