random remailers

[Eric Hughes <hughes@soda.berkeley.edu>]

>> Has anyone thought about the consequence of randomly picking a
>> remailing path instead of using the same one?  

>what if the remailer flips a coin, choosing between final delivery
>and remailing through another of its ilk.  "message delivery with
>probability one ..."

This is an excellent suggestion.  I have to think about the
mathematical properties some more, but a few spring to mind.  Assume,
for discussion, that there is constant probability of delivery at each
hop, say p.

First, the expected number of hops is 1/p.  To see this just sum the
following series.

	$ E(p) = \Sum_{n=1}^{\infinity} n p (p-1)^{n-1} $

Thus the syntax for routing can be extremely simple, just specifying
the expected number of hops wanted.  If you want to have guaranteed
minimum delivery, you can manually route through a few hops, then
randomize.

Eric