From: lcottrell@popmail.ucsd.edu (Lance Cottrell)
Date: Wed, 8 Feb 95 22:35:18 PST
To: Hal <cypherpunks@toad.com
Subject: Re: MIME based remailing commands
Message-ID: <ab5f62d802021004dd65@[137.110.24.250]>
MIME-Version: 1.0
Content-Type: text/plain


>Nathaniel Borenstein <nsb@nsb.fv.com> writes:
>
>>Excerpts from junk.interesting: 7-Feb-95 Re: MIME based remailing co..
>>"Perry E. Metzger"@imsi. (2553)
>
>>> > > It is being remailed via a MIME-based structure where two new
>>>content types
>>> > > are defined: multipart/remail and application/remail-commands.  The
>>> > > multipart/remail type is supposed to be composed of two parts, the
>>> > > application/remail-commands part which has remailer commands, and the
>>> > > other part which is the "payload" to be remailed.
>
>>Perhaps you might consider writing up an informational RFC to define
>>these types?  I think that would be very useful. -- Nathaniel
>
>Well, that was just an example; I was making those names up off the top
>of my head in order to concretize what I understood Perry was suggesting.
>
>I can see that putting remailer commands into a specific part of a MIME
>multipart message has some advantages.  Right now we are basically
>having the remailing commands be mail header fields.  But really people
>aren't supposed to just make up new fields like that.  I think the
>"name space" of these fields is protected somewhat more than many other
>aspects of communication protocols on the net.  Is there precedent for
>adding service-by-mail functionality in this way?  I am not completely
>comfortable with it.  And as we think of new functionality and new
>commands they all have to get added at this top level, the same
>visibility and name space as "Subject", "From", and "To".
>
>OTOH it does have the advantage that it is easy to do, at least with the
>"::" pasting token idea (which perhaps would need to be documented in its
>own right).
>
>If we did use a separate message part we'd have our own little name space
>to use, with no fears of conflicting with someone else.  (Maybe "Latency"
>might be used in a future extension of RFC822 for some other meaning than
>what we are using it for.)  I am not sure what has to be done to get an
>RFC approved but I suspect that adding mail header fields would be much
>more likely to hit opposition than adding yet another MIME type.
>
>What does Mixmaster use for its commands?  Does it use "::" followed by
>Anon-Send-To: and such?  Or some other format?  Maybe it should be made
>MIME compliant from the beginning.  This way we are moving with the
>current, the flow of the net, rather than across it.
>
>Hal

With Mixmaster, everything is hidden inside the encrypted and ascii armored
message structure.

I use the :: token to let the remailer know that this is a remailer message
of some sort. The Remailer-Type will eventually be used to indicate the
version that created the message. It would be easy to add support for MIME.
It would just replace the token and version number.

All remailing instructions are inside the ascii armor.
Note that the block of ascii armor is allways exactly the same length.

::
Remailer-Type: 2.0

-----BEGIN REMAILER MESSAGE-----
hQCMAgbmF1BLzawNAQP/RFw2/UagugMFPlnJ94KLmhaxDoplzAhNBCxuFRL2fosL
V1YnFd2XVckJJ6vTe6DB+POO+V7HEdXkp3sWtjb56Am+/B+tM1TdeC6NPNV4g5PC
15oYl7eD0ZxyjB34GdN5z/C2mOMbvP3k9eK3pn3ffkaXHBt1Y0I9ZieHkE6erxem
AAAAusuiqVunPh15+7gttD5pNuIAOFDKfH8NJ39ReSEFAeeiOun6KSneJT+2DJ9Q
LbK14WqsBVu1kDaUOHKchE9hPSFfTijTJp7I+GuiuOkDChUzZNZ21xpBS+8xMg58
0i61z9EEf11G0G5JShTaeaGWNd14QxoyrxjTh9PrItOz49M9lSY71KoTP2+fVc0h
xDGHw7iVeeToOtFqmDBI14FOVJz2rYuMu7vTD+MTwP3INkraCXqTeBoJ7g31Nhqj
<SNIP>
LbK14WqsBVu1kDaUOHKchE9hPSFfTijTJp7I+GuiuOkDChUzZNZ21xpBS+8xMg58
0i61z9EEf11G0G5JShTaeaGWNd14QxoyrxjTh9PrItOz49M9lSY71KoTP2+fVc0h
xDGHw7iVeeToOtFqmDBI14FOVJz2rYuMu7vTD+MTwP3INkraCXqTeBoJ7g31Nhqj
VYbH5jxvKPjF4HEaS++MaBwTvzBkEKxbS+6oh7G/ndkHBxA7d7C0sx+qX9sjJyAs
OIpGERZYA9RVspXUWys5fihnwrhk90dDAVZb8hTsPQfTXLp4
=ouPq
-----END REMAILER MESSAGE-----

--------------------------------------------------
Lance Cottrell  who does not speak for CASS/UCSD
loki@nately.ucsd.edu
PGP 2.6 key available by finger or server. Encrypted mail welcome.
Home page http://nately.ucsd.edu/~loki/
Check out my essay on the next generation remailer Mixmaster on the WWW page.
For anon remailer info, mail remailer@nately.ucsd.edu Subject: remailer-help

"Love is a snowmobile racing across the tundra.  Suddenly
it flips over, pinning you underneath.  At night the ice
weasels come."
                        --Nietzsche