From 76e8631e3134f151e2170ed7d9a96f68ea2b5339 Mon Sep 17 00:00:00 2001 From: jrandom Date: Thu, 7 Jul 2005 21:16:57 +0000 Subject: [PATCH] included IV tagging info --- router/doc/tunnel-alt.html | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/router/doc/tunnel-alt.html b/router/doc/tunnel-alt.html index 470876563..1b868e949 100644 --- a/router/doc/tunnel-alt.html +++ b/router/doc/tunnel-alt.html @@ -1,4 +1,4 @@ -$Id: tunnel-alt.html,v 1.6 2005/01/25 00:46:22 jrandom Exp $ +$Id: tunnel-alt.html,v 1.7 2005/02/16 19:48:18 jrandom Exp $ 
 1) Tunnel overview
 2) Tunnel operation
@@ -178,11 +178,14 @@ updates the IV by encrypting it with AES256/ECB using the participant's IV key,
 then forwards the tuple {nextTunnelId, nextIV, encryptedData} to the next hop.

 
 
Duplicate message detection is handled by a decaying Bloom filter on message
-IVs.  Each router maintains a single Bloom filter to contain all of the IVs for
-all of the tunnels it is participating in, modified to drop seen entries after 
-10-20 minutes (when the tunnels will have expired).  The size of the bloom 
-filter and the parameters used are sufficient to more than saturate the router's
-network connection with a negligible chance of false positive.

+IVs.  Each router maintains a single Bloom filter to contain the XOR of the IV and
+the first block of the message received for all of the tunnels it is participating
+in, modified to drop seen entries after 10-20 minutes (when the tunnels will have
+expired).  The size of the bloom filter and the parameters used are sufficient to
+more than saturate the router's network connection with a negligible chance of 
+false positive.  The unique value fed into the Bloom filter is the XOR of the IV 
+and the first block so as to prevent nonsequential colluding peers in the tunnel 
+from tagging a message by resending it with the IV and first block switched.

 
 
2.4) Endpoint processing