Re: MTS transparency and anonymity

>> in the envelope I recommend that MAIL FROM:<> be used.  a lot of
>> MTAs reject it these days, but they are clearly broken.
>
> I agree that it is wrong to reject null return paths altogether. 
> However
> your suggestion is incompatible with backscatter detection systems 
> (such
> as BATV or Signed Envelope Sender) which assume that null return paths 
> are
> only used for bounce messages.

those systems are operating on false assumptions.  it's never been the 
case that <> was limited to bounce messages.

> This idea of obfuscating the message header does not provide proper
> anonymity, since the trace fields will still contain the IP address of 
> the
> sender which is enough to identify them. Why isn't pseudonimity enough?
> Why not propose a specification for properly strong anonymity based on
> mixmaster or some other multi-stage cryptographic system?

I don't view this as trying to provide true anonymity, in the sense 
that the message cannot be traced. I view it as trying to provide a way 
to say "we don't know who actually sent this message, or whether he 
even has an email address".

Keith