From: eric@Synopsys.COM
Date: Fri, 27 Aug 93 20:56:02 PDT
To: cypherpunks@toad.com
Subject: Re: Attacks on remailers (LONG)
In-Reply-To: <9308271052.AA07922@achilles.ctd.anl.gov>
Message-ID: <199308280353.AA02675@gaea.synopsys.com>
MIME-Version: 1.0
Content-Type: text/plain


>>>>> On Fri, 27 Aug 93 05:52:43 CDT, b44729@achilles.ctd.anl.gov (Samuel Pigg) said:

Samuel> Correct me if I'm wrong, but as I see it, there are two goals
Samuel> for the remailers:

Samuel> (1) 	Anonymous addresses to which mail can be sent, but the recipient
Samuel> 	is unknown and cannot be determined (receiving anonymous mail).

Samuel> (2)	The ability to send mail to someone without anyone (including
Samuel> 	the recipient) determing that you did so (sending anonymous mail).

Samuel> Number 2 can be mostly taken care of with nested encryption of mail headers.


This is an excellent observation which many people seem to ignore when
thinking about anonymous remailers.  It's understandable why, because
achieving both of these goals at the same time is really quite
difficult.  I've been working on a system to accomplish this for
several months now, and it's quite complicated.  I call it SASE for
Self Addressed Stampable Envelopes.  Actually a new name that doesn't
imply prepaid postage would be nice if anyone can think of a catchy
one...

Samuel> To construct an anonymous address block might be something like:

Samuel> 	Anonymous Anne wants an anonymous address.
Samuel> 	First she generates a set of N keys (IDEA, DES or .......

That's basically the way SASE works.  It's important that some of the
keys be public key pairs, however; as you need to be able to publish
one half of a key, and seal the other half for an unpublished remailer
to decrypt with.

One thing is certain, these protocols are not simple.  We definitely
need people thinking about them...

-eric messick