Large Scale Simulation of Tor: Stream Mix Networks Low latency - - PowerPoint PPT Presentation

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Large Scale Simulation of Tor: Stream Mix Networks Low latency - - PowerPoint PPT Presentation

Apr 18, 2023 113 likes •330 views

Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O Gorman Anonymous Networks Large Scale Simulation of Tor: Stream Mix Networks Low latency Networks Network Correlation Attacks Simulation Results Attacks Gavin O

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SLIDE 1

Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Large Scale Simulation of Tor: Stream Correlation Attacks

Gavin O’ Gorman

Dublin City University

December 8, 2007

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Anonymous networks

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Proxy

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Simple Mix

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Cascade Mix

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Free Cascade Mix

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Low latency network

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Traffic Analysis

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Currently deployed anonymous networks

◮ Over 1500 nodes ◮ Over 100 countries ◮ Hundreds of thousands on connections through the

network

◮ Theorized traffic analysis attacks

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Currently deployed anonymous networks

◮ Over 1500 nodes ◮ Over 100 countries ◮ Hundreds of thousands on connections through the

network

◮ Theorized traffic analysis attacks ◮ How anonymous is a user ?

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

SSFNet

◮ Scalable Simulation Framework Network (SSFNet) ◮ Simulate TCP/IP, Ethernet, Socket interfaces ◮ Has HTTP/TCP generators. ◮ TCPDump compatible output ◮ Simulated Tor circuits, routing, traffic fragmentation ◮ US ISP Topology ◮ 6,000 nodes ◮ Run the simulation for 1060 seconds to settle and then

60 for data

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Tor Simulation Process

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Results

◮ Probability of correctly identifying streams entering the

network with streams exiting the network

◮ Several attacks used

◮ Start and End timing ◮ Packet counting ◮ Cross-Correlation - Pearson Function

◮ Run the attacks with increasing numbers of streams ◮ Don’t know the transit time, so have to test

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Start & End stream timing

◮ Compare the start and end times of streams ◮ 98% to 94% of streams filtered

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Packet counting

◮ Count the number of cells in a stream ◮ 5% to 15% of streams are removed.

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Cross-Correlation

r(d) =

  • i((xi − µ)(x′

i+d − µ′))

  • i(xi − µ)2
  • i(x′

i+d − µ′)2 ◮ Set a windows size W and count the number of packets

received

◮ xi is the ith packet count of stream x ◮ x′ i is the ith packet count of stream x′ ◮ µ is the average of packet counts in stream x ◮ d is the variable delay value

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Cross-Correlation

20 40 60 80 100 5 10 15 20 25 Percentage of streams correctly correlated Number of ASs Fixed time window of 1s attack

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Conclusion

◮ Initial results show promise ◮ Future work the simulation will allow us to:

◮ Introduce delay and measure QoS & Anonymity ◮ Test active attacks ◮ Modify Tor protocol to account for specific attacks

scenarios

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Thank you!

◮ Thanks for listening and thanks to Science Foundation

Ireland

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Large Scale Simulation of Tor: Stream Correlation Attacks Gavin O’ Gorman Anonymous Networks

Mix Networks Low latency Networks

Network Simulation Results

Attacks

Conclusion

Any questions ?