1. © 2005, it - instituto de telecomunicações. Todos os direitos reservados. Anonymity in Wireless Networks Under Traffic Analysis Attacks Hugo Moreira de Sousa Pinto Professor Daniel Lucani Professor João Barros

2. 2 Security in Communications  Measures to deter violations that involve the transmission of information  Anonymity – hiding the parties involved in a communication Anonymity in Wireless Networks Under Traffic Analysis Attacks IJUP - 18th February 2011  Authentication  Access Control  Data Integrity  Non Repudiation  Data Confidentiality  Scheduling mechanisms  Dummy transmissions  Wireless Networks  Session anonymity

3. 3 Problem Setup Anonymity in Wireless Networks Under Traffic Analysis Attacks IJUP - 18th February 2011 A1A2A3 Wireless Line network  Types of sessions  Unicast Sessions:  e.g. VoIP conversation  Multicast Sessions:  e.g. Sharing a picture A1A2 A1A2A3 A1 A2 A1 -> {A2,A3} Possible sessions A1 A2 A2 A3 A1 A3 A1 -> {A2, A3} A2 -> {A1, A3} A3 -> {A1, A2}

4. 4 Scheduling – 3 node line network  Pattern 1  Pattern 2 Anonymity in Wireless Networks Under Traffic Analysis Attacks IJUP - 18th February 2011 t1t1 t2t2 t3t3 t4t4 A1 A2xxxx A3 t1t1 t2t2 t3t3 t4t4 A1x A2xx A3x Possible sessions A1 A2 A2 A3 A1 A3 A1 -> {A2, A3} A2 -> {A1, A3} A3 -> {A1, A2} Not Anonymous Anonymous Possible sessions A1 A2 A2 A3 A1 A3 A1 -> {A2, A3} A2 -> {A1, A3} A3 -> {A1, A2} Possible sessions A1 A2 A2 A3 A1 A3 A1 -> {A2, A3} A2 -> {A1, A3} A3 -> {A1, A2}

5. 5 Design Objectives  Provide session anonymity Anonymity in Wireless Networks Under Traffic Analysis Attacks IJUP - 18th February 2011 t1t1 t2t2 t3t3 t4t4 t5t5 t6t6 A1 A2 A3 A4 A5 A6  Maximize throughput  Minimize energy  Possibility of simultaneous transmissions  Scalable to longer networks A1A2A3A4A5A6 t1t1 t2t2 t3t3 t4t4 t5t5 t6t6 A1X A2 A3 A4X A5 A6 t1t1 t2t2 t3t3 t4t4 t5t5 t6t6 A1X A2XX A3XX A4XX A5XX A6X

6. 6 Cost of anonymity Anonymity in Wireless Networks Under Traffic Analysis Attacks IJUP - 18th February 2011 A1A2A3A4A5 K=3  For k>=5 we have free anonymity in terms of throughput

7. 7 Conclusions and future work  Session anonymity  No cost in throughput  High cost in energy if the network size is too long  Use of transmission mechanisms such as network coding  Double throughput  Reduce energy consumption by half  Study trade-offs between anonymity and cost  Look into different network topologies Anonymity in Wireless Networks Under Traffic Analysis Attacks IJUP - 18th February 2011