Re: Nymservers and replay attacks?

[David Mazieres <dm@scs.cs.nyu.edu>]

> Date: Wed, 20 Mar 2002 14:34:00 -0500
> From: Roger Dingledine <arma@mit.edu>
> 
> I've been pondering the reply block issue some more, and I realized I
> don't actually know how the current mixmaster/nymserver system works.
> 
> The nymserver has an email address and keeps an associated reply block
> with it. People send mail to the nym address, and the nymserver forwards
> it to the reply block. Is that about it?
> 
> Does the remailer system drop replays? How could that work?
> 
> Is it that the remailer system is generally type 2 remailers, and the
> nymserver uses type 1 (which don't drop replays)?
> 
> So is it really the case that nobody has figured out how to do long-lived
> reply blocks in the face of servers that drop replays?

This is correct.  The nymserver uses type-1 reply blocks.  You can
replay any type-1 message leaving the back end of the nymserver.

David