From: Derek Atkins <warlord@MIT.EDU>
Date: Tue, 23 Feb 93 15:53:46 PST
To: J. Michael Diehl <mdiehl@triton.unm.edu>
Subject: Re: Newbie comments.
In-Reply-To: <9302232326.AA26860@triton.unm.edu>
Message-ID: <9302232352.AA05451@toxicwaste.MEDIA.MIT.EDU>
MIME-Version: 1.0
Content-Type: text/plain


> But I have a (newbie?) question.  Isn't it true that, at the network
> level, it is still possible to tell where a message came from and
> where it's going.  That is, given the proper motivation, couldn't "and
> entity" sniff out all of this information and find out which machine a
> particular message came from.  And from logs at that machine, which
> The Entity naturally has access to, It could find out who send the
> message.  Just wondering.....

That is the point of encrypted, anonymous remailers.  Since the
message is encrypted, it looks like a random set of bits.  If it gets
re-encrypted at every stage, then the remailers can add random bits of
data to change the size.  They already change the headers.

So, the only thing left to worry about is a FIFO problem.  But that
is easily solved.

So, here is what happens:
  A message comes into a remailer (actually, a bunch of messages do,
but that's not important).  It comes in encrypted, so you can't read
the message.  The headers are stripped off in the remailer and the
message is re-encrypted, so the data changes.  If it gets stored an
arbistrary length of time, and the outgoing order is different than
the incoming order, than there is no way to figure out which message
came from or went to where.

There is a lot more to this, and a lot of other problems that need to
be solved, but this is it in a nutshell.

I hope it answers your question.  I'm sure people will correct any
mistakes I inadvertantly left in.

-derek

PGP 2 key available upon request, on the key-server:
	pgp-public-keys@toxicwaste.mit.edu
--
  Derek Atkins, MIT '93, Electrical Engineering and Computer Science
      Chairman, MIT Student Information Processing Board (SIPB)
           MIT Media Laboratory, Speech Research Group
           warlord@MIT.EDU       PP-ASEL        N1NWH