\section{Publication Systems}

Along with the need for more research on communications channels, there
are a number of other issues we should address more thoroughly. These include:

\begin{description}
\item[Formalizing Anonymity] The notions that we present in Chapter
\ref{chap:anon} are an excellent beginning for talking about the amount
of anonymity a publishing system provides. However, we still have no real
formal definitions for these concepts. By
thoroughly enumerating the capabilities of potential adversaries, along
with describing what their goals might be and what it means for them to
achieve each goal, we could gain much more insight into the nature of anonymity
and how it relates to other notions such as confidentiality.
\item[Ideal Mixnet] Many of the aspects of anonymity that we hope to
achieve are going to be very difficult without a more anonymous
communications channel. In order to provide a more anonymous publication
service, we need to solve the mixnet design problem.
\item[Deployed Mixnet] Apart from developing the design for a better
mixnet, we need to actually get a functional communications channel
out on the internet. Without a large number of nodes running and
available in a free environment, our anonymity requirements cannot be
achieved. It would probably be very effective to distribute binary packages (e.g.,
in {\tt RPM} format) to ease installation.
\item[Deploying, Testing, and Evaluating] Free Haven is only a set of
designs for an anonymous publishing service. We discovered a number of
important ideas while implementing our proof of concept; however, actually
finishing and testing the implementation would teach us a lot more about
how stable and reliable Free Haven will be.
\item[The buddy system] Free Haven provides a much stronger level of anonymity
than related works; however, this amount of anonymity requires us to
include some method of accountability to ensure that servers are behaving
according to protocol. The current buddy system is insufficient for a
number of reasons. We must find a better accountability mechanism.
\item[Flooding protection] Because we are using a mixnet which emphasizes
anonymity, there are currently no flooding protection mechanisms in place.
We need to devise some intelligent ways of bandwidth-throttling, to encourage
more people to be willing to run mixnet or servnet nodes.
\item[Modelling to determine optimal parameters] 
We should describe some mechanisms for modelling Free Haven based on various parameters
of $k$, $n$, number of documents, frequency of trading, percentage of malicious
nodes, etc. Building a good model for Free Haven that is extensible enough to
cover other anonymous publishing systems such as Freenet would benefit the
community as well.
\item[Alternate Payment Schemes] We currently avoid the requirement for payments --
instead, our `economy of trust' rewards successfully storing data with the
offer to store data in return. We should investigate alternate mechanisms for decentralized
currency and payment.
\item[Education and legal awareness] Although there are a few papers (e.g. \cite{CATO})
which succinctly and accurately summarize case law and current legislative
opinion about anonymity on the internet, most programmers and other
enthusiasts are disturbingly ignorant on this topic. Collecting and coordinating 
an easily readable archive of such documents would be a great benefit to the
community.
\end{description}

