Re: SMTP service (was: Reply blocks and tagging protection: a thirdvariant)

[Nick Mathewson <nickm@alum.mit.edu>]

On Wed, 2002-04-10 at 12:30, George Danezis wrote:
>
>On Tue, 9 Apr 2002, Zooko wrote:
>
>>Then I think of the SMTP stuff (in, out, or both, whether nymserver or 
>>anonymous) as being a service that a mixminion node can offer to the world.  
>>"Send me your e-mail and I'll poke it through the mixnet for you."
 [...]
> Indeed I had this model in mind as well. The constrain I was working with 
> all this time was that the people benefiting should be running special 
> software while others should not. 

Let's make a distinction between "anonymous recipients must run special
software" (which seems to be inescapable) and "anonymous recipients must
run a (restricted) servers" (which is avoidable).

 [...]
> I accept that in some cases this is not possible (since people might be 
> off-line) and therefore we need a pull rather than push mechanism for 
> final delivery. I do not think it is wise to assume that Email will 
> satisfy us. In particular if email is allowed we allow MixMinion to be 
> used to perform Mail Bombing. Maybe something else would be more 
> appropriate.

I agree that SMTP presents difficulties, but let's consider that issue
separately.

Instead, let's concentrate on whether delivery information needs to go
into the header or not.  _That_ was the question I thought Zooko was
asking.  I think that my last email made a pretty good case in favor of
it, and it seems (from your closing sentence below) that you might
agree.  Is this so?

 [...]
> We can use the 40 bytes of addressing to tell the final mix what is 
> expected from it.

Please see my last email for a more detailed explanation of why I think
delivery info can't go into the payload.  If we agree it goes in the
header, then we can figure out how to distinguish delivery headers, and
what to do if we ever need more than 40 bytes of delivery info.

Yours,
-- 
Nick