Remailer Functions (Re: Testing for encryption. (fwd))

[Jim Choate]

Which raises an interesting question for me, Plan 9 has no remailer and
I've decided to take that on as a first project. However, I want to
combine the features of say majordomo with several different sorts of
anonymity (ranging from stripping From: headers to full encryption). For
the time being I'm refering to it as 'igor'.

I believe fundamentally that putting routing info in the body of the
traffic is evil. So I intend to use the Subject: with default delimiters
(ie [igor: *]). So if you wanted to send to SSZ CDR under igor and strip
your headers the command might be Subject: Foobar [igor: strip_header].
The [*] is itself always stripped. There will also be a no_log that won't
log the receipt or transmission in any system file. You could of course
chain commands. While I do intend to allow igor to use a 'set' of trusted
remailers using PKE the actual selection of remailers will be decided by
the listproc and not the user. They'll only be able to do, for example,

[igor: encrypt, mix, strip_header, no_log, check_pgp]

This would for example encrypt the body using the inter-igor PK's. It
would send the email w/ cover traffic to some number of remailers (maybe
mix_# also?). It would strip the header before it did anything so in
effect the recipient will see the last remailers header and that's it. No
log would instruct all igor nodes to not log the traffic. And finally it
would ensure that the original source traffic fit the PGP format (it would
support other algorithms through loadable modules.

Inter-igor traffic relating to a particular piece of mail would be wrapped
around the actual traffic under question (the body would never be touched
by igor's hands directly). I've still not decided exactly what scope this
command set will cover.

With respect to mix, what I intend is each igor will have a list of
trusted single-hop receivers. It will randomly select n (or m if n>m) of
these and use the PK's to encrypt the traffic. It will only send/receive
from this trusted list. So if you tell igor to use 3 layers of remailer
then each node can only know of it's immediate neighbors and won't have
any way of determining where any neighbor received it from (Yes, the
wording of the last couple of sentences is a tad vague).

It will of course support the sorts of features that majordomo has as
well.

What other sorts of features might be useful?

---------- Forwarded message ----------
Date: Thu, 22 Feb 2001 12:07:23 -0800
From: David Honig <honig at sprynet.com>

Actually these functions belong in the listserver (remailer) not the SMTP
agent.

1. filter on: 
	list of acceptable substrings such as headers, 'CDR:' tokens, etc.; and/or 
	entropy threshold and/or; 
	recognized digsigs from members of the list

2. decrypt

3. for each list member
	encrypt msg from previous step and send


    ____________________________________________________________________

           Before a larger group can see the virtue of an idea, a
           smaller group must first understand it.

                                           "Stranger Suns"
                                           George Zebrowski

       The Armadillo Group       ,::////;::-.          James Choate
       Austin, Tx               /:'///// ``::>/|/      ravage at ssz.com
       www.ssz.com            .',  ||||    `/( e\      512-451-7087
                           -====~~mm-'`-```-mm --'-
    --------------------------------------------------------------------