mirror of
https://gitlab.torproject.org/tpo/core/tor.git
synced 2024-11-10 13:13:44 +01:00
Small changes in design goals. Starting analysis section.
svn:r694
This commit is contained in:
parent
161eac5093
commit
3d21eade6b
@ -80,8 +80,8 @@ is sent in fixed-size \emph{cells}, which are unwrapped by a symmetric key
|
||||
at each node (like the layers of an onion) and relayed downstream. The
|
||||
original Onion Routing project published several design and analysis
|
||||
papers
|
||||
\cite{or-jsac98,or-discex00,or-ih96,or-pet00}. While there was briefly
|
||||
a wide area Onion Routing network,
|
||||
\cite{or-jsac98,or-discex00,or-ih96,or-pet00}. While there was
|
||||
a wide area Onion Routing network for a several weeks,
|
||||
% how long is briefly? a day, a month? -RD
|
||||
the only long-running and publicly accessible
|
||||
implementation was a fragile proof-of-concept that ran on a single
|
||||
@ -400,9 +400,9 @@ enable connections between mutually anonymous entities, also
|
||||
facilitate connections to hidden servers. These building blocks to
|
||||
censorship resistance and other capabilities are described in
|
||||
Section~\ref{sec:rendezvous}. Location-hidden servers are an
|
||||
essential component for anonymous publishing systems such as
|
||||
Publius\cite{publius}, Free Haven\cite{freehaven-berk}, and
|
||||
Tangler\cite{tangler}.
|
||||
essential component for the anonymous publishing systems such as
|
||||
Eternity\cite{eternity}, Publius\cite{publius},
|
||||
Free Haven\cite{freehaven-berk}, and Tangler\cite{tangler}.
|
||||
|
||||
|
||||
STILL NOT MENTIONED:
|
||||
@ -410,9 +410,6 @@ real-time mixes\\
|
||||
rewebbers\\
|
||||
cebolla\\
|
||||
|
||||
Rewebber was mentioned in an earlier version along with Eternity,
|
||||
which *must* be mentioned if we cite anything at all
|
||||
in censorship resistance.
|
||||
|
||||
[XXX Close by mentioning where Tor fits.]
|
||||
|
||||
@ -444,6 +441,16 @@ Tor's evolution.
|
||||
% for Alice if she's using some other http proxy somewhere. I guess the
|
||||
% external http proxy should route through a Tor client, which automatically
|
||||
% translates the foo.onion address? -RD
|
||||
%
|
||||
% 1. Such clients do benefit from anonymity: they can reach the server.
|
||||
% Recall that our goal for location hidden servers is to continue to
|
||||
% provide service to priviliged clients when a DoS is happening or
|
||||
% to provide access to a location sensitive service. I see no contradiction.
|
||||
% 2. A good idiot check is whether what we require people to download
|
||||
% and use is more extreme than downloading the anonymizer toolbar or
|
||||
% privacy manager. I don't think so, though I'm not claiming we've already
|
||||
% got the installation and running of a client down to that simplicity
|
||||
% at this time. -PS
|
||||
\item[Usability:] A hard-to-use system has fewer users---and because
|
||||
anonymity systems hide users among users, a system with fewer users
|
||||
provides less anonymity. Usability is not only a convenience for Tor:
|
||||
@ -459,7 +466,12 @@ Tor's evolution.
|
||||
solved by Tor; it would be beneficial if future systems were not forced to
|
||||
reinvent Tor's design decisions. (But note that while a flexible design
|
||||
benefits researchers, there is a danger that differing choices of
|
||||
extensions will render users distinguishable. Thus, implementations should
|
||||
extensions will render users distinguishable. Thus, experiments
|
||||
on extensions should be limited and should not significantly affect
|
||||
the distinguishability of ordinary users.
|
||||
% To run an experiment researchers must file an
|
||||
% anonymity impact statement -PS
|
||||
of implementations should
|
||||
not permit different protocol extensions to coexist in a single deployed
|
||||
network.)
|
||||
\item[Conservative design:] The protocol's design and security parameters
|
||||
@ -1376,6 +1388,30 @@ client doesn't include the right cookie with its request for service,
|
||||
the server doesn't even acknowledge its existence.
|
||||
|
||||
\Section{Analysis}
|
||||
\label{sec:analysis}
|
||||
|
||||
In this section, we discuss how well Tor meets our stated design goals
|
||||
and its resistance to attacks.
|
||||
|
||||
Goals:
|
||||
\begin{description}
|
||||
\item [Basic Anonymity:] Because traffic is encrypted, changing in
|
||||
appearance, and can flow from anywhere to anywhere within the
|
||||
network, a simple observer that cannot see both the initiator
|
||||
activity and the corresponding activity where the responder talks to
|
||||
the network will not be able to link the initiator and responder.
|
||||
Nor is it possible to directly correlate any two communication
|
||||
sessions as coming from a single source without additional
|
||||
information. Resistance to specific anonymity threats will be discussed
|
||||
below.
|
||||
|
||||
\item[Deployability:]
|
||||
|
||||
\item[Usability:]
|
||||
\item[Flexibility:]
|
||||
\item[Conservative design:]
|
||||
\end{description}
|
||||
Basic
|
||||
|
||||
How well do we resist chosen adversary?
|
||||
|
||||
@ -1497,26 +1533,57 @@ them.
|
||||
\begin{enumerate}
|
||||
\item \textbf{Passive attacks}
|
||||
\begin{itemize}
|
||||
\item \emph{Simple observation.}
|
||||
\item \emph{Observing user behavior.}
|
||||
\item \emph{Timing correlation.}
|
||||
\item \emph{Size correlation.}
|
||||
\item \emph{Option distinguishability.}
|
||||
\item \emph{Option distinguishability.} User configuration options.
|
||||
A: We standardize on how clients behave. cite econymics.
|
||||
|
||||
\item sub of the above on exit policy\\
|
||||
Partitioning based on exit policy.
|
||||
|
||||
Run a rare exit server/something other people won't allow.
|
||||
|
||||
DOS three of the 4 who would allow a certain exit.
|
||||
|
||||
\item Content analysis. Not our main thing, but, Privoxy to
|
||||
anonymization of data stream.
|
||||
|
||||
|
||||
\end{itemize}
|
||||
|
||||
\item \textbf{Active attacks}
|
||||
\begin{itemize}
|
||||
\item \emph{Key compromise.}
|
||||
\item \emph{Iterated subpoena.}
|
||||
\item \emph{Run recipient.}
|
||||
\item \emph{Run a hostile node.}
|
||||
\item \emph{Compromise entire path.}
|
||||
\item \emph{Selectively DoS servers.}
|
||||
\item \emph{Key compromise.} Talk about all three keys. 3 bullets
|
||||
\item \emph{Iterated subpoena.} Legal roving adversary. Works bad against
|
||||
this because of ephemeral keys. Criticize pets paper in section 2 for
|
||||
failing to consider this when describing roving adversary.
|
||||
\item \emph{Run recipient.} Be the Web server.
|
||||
\item \emph{Run a hostile node.}
|
||||
\item \emph{Compromise entire path.} Directory servers controlling admission
|
||||
to network. But if you do compromise it, we're toast.
|
||||
\item \emph{Selectively DoS OR.} Flood the pipe. We're toast. Rate limiting.
|
||||
We can't stop flooding creates through all your neighbors. Router twins
|
||||
is a useful fallback, makes you hit all the twins.
|
||||
\item \emph{Introduce timing into messages.}
|
||||
\item \emph{Tagging attacks.}
|
||||
Integrity checking stops this.
|
||||
|
||||
Subcase of running a hostile node:
|
||||
the exit node can change the content you're getting to try to
|
||||
trick you. similarly, when it rejects you due to exit policy,
|
||||
it could give you a bad IP that sends you somewhere else.
|
||||
\end{itemize}
|
||||
\item \emph{replaying traffic} Can't in Tor. NonSSL anonymizer.
|
||||
|
||||
\item Do bad things with the Tor network, so we are hated and
|
||||
get shut down. Now the user you want to watch has to use anonymizer.
|
||||
|
||||
Exit policy's are a start.
|
||||
|
||||
\item Send spam through the network. Exit policy (no open relay) and
|
||||
rate limiting. We won't send to more than 8 people at a time. See
|
||||
section 5.1.
|
||||
|
||||
we rely on DNS being globally consistent. if people in africa resolve
|
||||
IPs differently, then asking to extend a circuit to a certain IP can
|
||||
|
Loading…
Reference in New Issue
Block a user