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@@ -268,9 +268,9 @@ open problems.
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Modern anonymity designs date to Chaum's Mix-Net\cite{chaum-mix} design of
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1981. Chaum proposed hiding sender-recipient connections by wrapping
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messages in several layers of public key cryptography, and relaying them
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-through a path composed of Mix servers. Mix servers in turn decrypt, delay,
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-and re-order messages, before relay them along the path towards their
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-destinations.
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+through a path composed of ``Mixes.'' These mixes in turn decrypt, delay,
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+and re-order messages, before relaying them along the sender-selected
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+path towards their destinations.
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Subsequent relay-based anonymity designs have diverged in two
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principal directions. Some have attempted to maximize anonymity at
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@@ -643,33 +643,35 @@ the connection are unique enough. (This is not to say that Tor offers
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no resistance to traffic confirmation; it does. We defer discussion
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of this point and of particular attacks until Section~\ref{sec:attacks},
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after we have described Tor in more detail.)
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-
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-\SubSection{Known attacks against low-latency anonymity systems}
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-\label{subsec:known-attacks}
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-% Should be merged into ``Threat model'' and reiterated in Attacks. -NM
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-
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-We discuss each of these attacks in more detail below, along with the
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-aspects of the Tor design that provide defense. We provide a summary
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-of the attacks and our defenses against them in Section~\ref{sec:attacks}.
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-
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-Passive attacks:
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-simple observation,
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-timing correlation,
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-size correlation,
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-option distinguishability,
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-
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-Active attacks:
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-key compromise,
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-iterated subpoena,
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-run recipient,
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-run a hostile node,
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-compromise entire path,
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-selectively DOS servers,
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-introduce timing into messages,
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-directory attacks,
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-tagging attacks,
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-smear attacks,
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-entrapment attacks
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+% XXX We need to say what traffic analysis is: How about...
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+On the other hand, we {\it do} try to prevent an attacker from
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+performing traffic analysis: that is, attempting to learn the communication
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+partners of an arbitrary user.
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+% XXX If that's not right, what is? It would be silly to have a
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+% threat model section without saying what we want to prevent the
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+% attacker from doing. -NM
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+% XXX Also, do we want to mention linkability or building profiles? -NM
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+
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+Our assumptions about our adversary's capabilities imply a number of
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+possible attacks against users' anonymity. Our adversary might try to
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+mount passive attacks by observing the edges of the network and
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+correlating traffic entering and leaving the network: either because
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+of relationships in packet timing; relationships in the volume of data
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+sent; [XXX simple observation??]; or relationships in any externally
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+visible user-selected options. The adversary can also mount active
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+attacks by trying to compromise all the servers' keys in a
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+path---either through illegitimate means or through legal coercion in
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+unfriendly jurisdiction; by selectively DoSing trustworthy servers; by
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+introducing patterns into entering traffic that can later be detected;
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+or by modifying data entering the network and hoping that trashed data
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+comes out the other end. The attacker can additionally try to
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+decrease the network's reliability by performing antisocial activities
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+from reliable servers and trying to get them taken down.
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+% XXX Should there be more or less? Should we turn this into a
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+% bulleted list? Should we cut it entirely?
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+
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+We list these attacks and more, and describe our defenses against them
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+in Section~\ref{sec:attacks}.
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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