[freehaven-dev] eternity USENET comparison

[Adam Back <adamb@zeroknowledge.com>]

In the freehaven paper in table 3.1: Overview: Computational 
Anonymity, Eternity USENET is listed as providing publisher
anonymity only.

- Eternity USENET actually provides pretty aggressive
Reader Anonymity: consider how hard it would be to track
down which internet users read a given alt newsgroup post.

The confusion may come from the availability of two modes of
use of the Eternity USENET client: local proxy, and public
proxy.  The public proxy is just to give people something
to play with without having to install software.  The local
proxy version provides reader anonymity.

- Eternity USENET doesn't provide server anonymity, but
it doesn't need to because all USENET servers are coopted
into being servers, and there are many of them.  It doesn't
provide server anonymity for public proxies, but service
remains available to local proxies if public proxies are
taken down.

- Also Eternity USENET provides document anonymity, the
USENET article can be encrypted with a key derived from the 
URL.  

Also for Eternity USENET public proxies they have the
option of encrypting their cache contents based on URL which
provides weak deniability -- at least it doesn't currently
know the URL, or stored document contents, though it must 
see the URL and content during access as there is no client
software in this mode.


Eternity USENET has it's problems, which are:

- for the local proxy client, the user only sees 
documents broadcast since it installs the software.
To fix this the author, interested reader, or agent
would have to periodically republish documents.

- scalability - there must be a limit to how many 
megabytes per day of Eternity USENET posts will be 
tolerated by USENET server admins.  alt.anonymous.messages
may be dropped in retaliation.  Of course Eternity USENET
can work from any and all USENET groups, but the act of
posting lots of unreadable binaries to arbitrary newsgroups
would be considered abusive.

- the race condition you discuss -- my thoughts on a way 
to combat this would be to do a bit commitment to the document
first, leave it a few days to distribute, then publish the
document proper.

- For the open public proxies, their problems are the 
limited number in existance, lack of server anonymity 
coupled with limited number of servers.


Also section 3.2.3 on Eternity USENET comments that the
participating servers have to already host USENET news.
This is wrong.  All the participating public server, or
local proxy client needs is access to a USENET server.

I ran a local proxy client for a while over a dial up
line with the local proxy client talking to the ISPs
news server using NNTP.

Adam