Cost to defeat the N-1 Attack Neil Chettiar

Plan Modify a pool mix to output n+k messages for every n input messages. MIX

How costly is it? Always maintain a pool of k dummy messages. Use a random function to decide if the mix should or should not send out k dummy messages. Use Heartbeat traffic to check if an N-1 attack is in progress, use this information to weigh the decision. Set a Time-To-Live value for the dummy traffic.

Focus Points Does the strategy really beat the N-1 attack? How is the pool Mix triggered: OR/AND, Dynamic Threshold? Set limits of the number of dummy messages used. How expensive is it to use the Dummy messages? Cases when HeartBeat strategy gets wrongly triggered. Extreme situations when the proposed random function fails to defeat the N-1 attack.

Resources 1. On blending attacks for mixes with Memory extended version. 2. Regroup-And-Go mixes to counter the (n-1) attack. 3. Active attacks on Reputable mix Networks. 4. Heartbeat traffic to counter (n-1) attacks. 5. A Least Squares approach to the static traffic analysis of high-latency anonymous communication systems. 6. Untraceable electronic mail, return addresses and digital pseudonyms. 7. From a trickle to a Flood: Active attacks on several Mix types. 8. Real-Time Mixes: A Bandwidth-Efficient anonymity protocol.

Questions?