More thoughts on From: lines

["Lucky Green" <shamrock@cypherpunks.to>]

To follow up on yesterday's discussion, I would like to slightly clarify
my comments made at the BoF.

The issue, as I understand it, is if mixminion should support From:
lines to be set by an entity other than the exit hop remailer operator.
If that is indeed the issue, I contend the following:

1) Persistent nyms benefit if the From: line on emails sent by that nym
match that nym's name and nymserver email address. Without this feature,
adoption of mixminion is bound to be negatively affected.

2) Enabling end-users to set the From: line to an arbitrary value has
historically been shown to cause persistent abuse. It is for this reason
that I stated that no system for which postmaster forwards to me will
ever operate a remailer that permits the sender to arbitrarily set the
From: line.

I do not believe that these two requirements are mutually exclusive.

The holders of persistent nyms have no need to set the From: line to an
arbitrary value. They solely have the need to set the from line to
reflect that of their, and only their, nym server email address.

A design in which the exit remailer sets the From: line to the nym and
email address of the user of a nym server who has proven to the exit hop
possession of the private key that authenticates the user to the nym
server for that account is not just acceptable, but I believe very
desirable. Offering that feature may well be required for mixminion to
attract new types of users.

--Lucky