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[freehaven-cvs] Reformat figures, add figure 2, shrink table.
Update of /home/freehaven/cvsroot/doc/pynchon-gate
In directory moria.mit.edu:/tmp/cvs-serv13874
Modified Files:
pynchon.tex
Log Message:
Reformat figures, add figure 2, shrink table.
Index: pynchon.tex
===================================================================
RCS file: /home/freehaven/cvsroot/doc/pynchon-gate/pynchon.tex,v
retrieving revision 1.44
retrieving revision 1.45
diff -u -d -r1.44 -r1.45
--- pynchon.tex 17 Sep 2004 23:20:42 -0000 1.44
+++ pynchon.tex 18 Sep 2004 00:01:06 -0000 1.45
@@ -34,6 +34,11 @@
\newcommand\CVol{\mbox{CVol}}
\newcommand\Vol{\mbox{Vol}}
+% Cut down on whitespace above and below figures displayed at head/foot of
+% page.
+\setlength{\textfloatsep}{3mm}
+% Cut down on whitespace above and below figures displayed in middle of page
+\setlength{\intextsep}{3mm}
\begin{document}
@@ -52,9 +57,7 @@
Bellevue, WA 98004 USA \\
\email{bram@bitconjurer.org}
\and
-The Free Haven Project\\
- 316 Brookline Street, Suite 3, \\
- Cambridge, MA 02139 USA \\
+ The Free Haven Project\\
\email{nickm@freehaven.net}
}
@@ -203,23 +206,22 @@
(SURBs)~\cite{surb} as a means of avoiding the replay attack issues. The
Type III protocol requires the recipient to create a large number of reply
blocks to be used by those who wish to send her mail. In practice, this is
-likely to be automated by a nym server~\cite{pop-mix} which will handle
-the storage of SURBs and transfer of pseudonymous mail through the
-remailer network to the recipient. The technique used in Type III also has
+likely to be automated by a nym server~\cite{pop-mix} that
+stores a number of SURBs and uses them to deliver pseudonymous mail to
+to the recipient---one such design is Underhill~\cite{underhill-spec}.
+The technique used in Type III also has
the property that the forward and reply messages share the same anonymity
set, which is a significant security improvement over Type I, and recent
work has been done by Danezis and Laurie on attack-resistant anonymous
packet formats suitable for reply messages~\cite{minx}. However, since
-reply blocks are still being used, reliability issues remain.\footnote
-{If any given node in the pre-selected SURB is defunct at the time mail is
+reply blocks are still being used, reliability issues remain.\footnote{If
+any given node in the pre-selected SURB is defunct at the time mail is
set to be delivered, the mail will be lost.} Reply block systems are also
susceptible to intersection attacks~\cite{disad-free-routes}. A global
observer can collect data on who is sending and receiving mail, and given
enough time and data, will be able to reliably determine who is talking to
whom via statistical correlation~\cite{statistical-disclosure}.
-%XXXX cite underhill
-
\subsubsection {Network-level client anonymity.}
The ZKS Freedom Network~\cite{freedom2-arch} provided anonymous IP access
to a POP3 server~\cite{freedom2-mail}, enabling its users to maintain
@@ -408,7 +410,8 @@
\subsection{Overview and Rationale}
The Pynchon Gate is a group of servers that provide anonymous message
-retrieval capabilities. A nym server receives messages for different
+retrieval capabilities (see figure~\ref{fig:pyn-arch}). A nym server receives
+messages for different
pseudonym accounts via email\footnote{The servers could also receive
messages through any suitable medium for message transfer, such as
``instant message'' systems~\cite{rfc-2779}. We require a
@@ -430,6 +433,14 @@
the adversary
cannot link the user to her pseudonyms.
+\begin{figure}
+\begin{center}
+\includegraphics[width=10cm, height=7cm]{figs/PynFig1}
+\caption{The Pynchon Gate Architecture}
+\label{fig:pyn-arch}
+\end{center}
+\end{figure}
+
This distributed-trust PIR-based message retrieval system lets us keep the
convenience,
reliability, and security of the ``send everything everywhere'' method,
@@ -442,15 +453,6 @@
We discuss the components of the Pynchon Gate architecture below.
-\begin{figure}
-\begin{center}
-\includegraphics[width=10cm, height=7cm]{figs/PynFig1}
-\caption{The Pynchon Gate Architecture}
-\label{pyn-arch}
-\end{center}
-\end{figure}
-%XXXX Reference this figure!
-
\subsection{The Nym Server}
The public-facing side of The Pynchon Gate consists of a nym server that
@@ -533,13 +535,19 @@
order), the first message bucket containing that user's messages, and a
digest of that bucket. Finally, the meta-index lists, for each index bucket,
the first and last $\UserID$ in that bucket, and a digest of that bucket.
-(See figure XXXX
-%XXXXX figure 2!!
-.)
+(See figure~\ref{fig:tree}.)
The index buckets and the message buckets together comprise the cycle's
"bucket pool." To ensure integrity, each bucket contains a hash of the
next bucket in the pool.
+\begin{figure}
+\begin{center}
+\includegraphics[width=10cm, height=7.5cm]{figs/PynFig2}
+\caption{The meta-index and bucket pool}
+\label{fig:tree}
+\end{center}
+\end{figure}
+
The metaindex is signed with the collator's private key, along with the index
of the cycle to which it applies.
@@ -769,7 +777,8 @@
We have evaluated the resource requirements of various nym server systems
described in section~\ref{subsec:related-work}, and compare their
-respective performance below. Bandwidth requirements for the independent
+respective performance in figure~\ref{fig:performance}. Bandwidth
+requirements for the independent
components of the pseudonym system are averages per cycle. We use the term
"infrastructure" to denote mix nodes in the Type I (Cypherpunk) and Type
III (Underhill~\cite{underhill-spec}) nym server systems, NNTP
@@ -796,10 +805,13 @@
PIR stream seed size is $SS$, and $K$ is the number of distributors chosen
from which to retrieve data.
-~
% XXXX This table is badly formatted, and doesn't fit on the page, but at
% least all the math is in it. Can a latex-ist fix?
\noindent
+\begin{figure}
+\begin{center}
+\begin{minipage}{\linewidth}
+\renewcommand{\thefootnote}{\thempfootnote}
{\tiny
\begin{tabular}{|r|c|c|c|c|}
\hline
@@ -814,7 +826,7 @@
$\CVol_i$ &
$\frac{2 \ell \sum \CVol_i}{S}$ &
$r N$ \\Type III nymserver
-\footnote{Underhill can be used in a full padding mode. In this case, the
+\footnote{\tiny Underhill can be used in a full padding mode. In this case, the
performance evaluation is the same, except that $CVol_i$ is calculated as
the maximum compressed volume a user can recieve, rather than the
average.} &
@@ -832,13 +844,21 @@
Pynchon Gate &
$\sum \Vol_i + \mbox{Pool} $ &
$\frac{1}{S}\left[ \sum \mbox{ClientB}_i + \mbox{Pool} \right]$ &
- $2 \mbox{ME} I + \mbox{Buckets}_i \left[ (K-1) SS + \frac{(m+I)}{8} + B
- \right] $ &
+% $2 \mbox{ME} I + \mbox{Buckets}_i \left[ (K-1) SS + \frac{(m+I)}{8} + B
+% \right] $ &
+ $2 \mbox{ME} I + \mbox{ClientPIRVol}$\footnote{\tiny ClientPIRVol is the
+amount of data sent and received during PIR, or
+ $\mbox{Buckets}_i \left[ (K-1) SS + \frac{(m+I)}{8} + B \right]$} &
$W \mbox{Pool}$
\\
\hline
\end{tabular}
}
+\end{minipage}
+\end{center}
+\caption{Performance comparison for several pseudonymity designs.}
+\label{fig:performance}
+\end{figure}
%\section{A Note on Usability}
%XXXX Merge into conclusion, where we evaluate our success.
%XXXX I don't mind chopping this whole section out if we need to. -LS.
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