Re: More thoughts on From: lines

[Len Sassaman <rabbi@abditum.com>]

On Tue, 25 Feb 2003, Lucky Green wrote:

> 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.

It is a requirement that nym users be able to set their From addresses to
that of the nym -- or, rather, that the nym server do so.

> 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 believe this must be in the spec.

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

They are not.

> 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.

Well, "they" (as in the user) should not be doing the setting. The nym
server should be.

> 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.

Is there any reason not to continue to permit nym servers to directly
deliver mail? I can't think of one.

(For the list members who weren't at the BoF: it was generally agreed
that, with regard to the standard recipient-viewable headers on
forward-only messages, everything should be removed except for Date: and
From:, which are set by the exit node, and To: and Subject:, which are set
by the user.)