[minion-cvs] partitioning attack is now slightly less dense

[arma@seul.org (Roger Dingledine)]

Update of /home/minion/cvsroot/doc
In directory moria.seul.org:/home/arma/work/minion/doc

Modified Files:
	minion-design.tex 
Log Message:
partitioning attack is now slightly less dense


Index: minion-design.tex
===================================================================
RCS file: /home/minion/cvsroot/doc/minion-design.tex,v
retrieving revision 1.88
retrieving revision 1.89
diff -u -d -r1.88 -r1.89
--- minion-design.tex	6 Nov 2002 06:08:18 -0000	1.88
+++ minion-design.tex	6 Nov 2002 06:30:13 -0000	1.89
@@ -1108,11 +1108,14 @@
 is valid --- also has problems. Specifically, it introduces a new class
 of \emph{partitioning} attacks, where the adversary can distinguish and
 track messages based on timestamps. If messages have short lifetimes,
-legitimate messages may arrive after their expiration date and be
-dropped. But if we specify expiration dates well after when we expect
-messages to arrive, messages arriving near their expiration date will be
-rare: an adversary can delay a message until near its expiration date,
-then release it and trace it through the network.
+meaning messages that take more than the average transit time through the
+mix expire before they reach the end of their path, then some legitimate
+messages will be dropped. But if messages have long lifetimes, meaning
+almost no messages in the system will be close to expiring, then messages
+arriving near their expiration date will be rare. An adversary can exploit
+this fact by intentionally delaying a message until near its expiration
+date and then releasing it. If he owns a mix later in the path he can
+recognize the message because it will stand out.
 
 % need to read stop & go mix paper here. -RRD