1. 研 究 生：蔡憲邦 指導教授：柯開維 博士 Design of Efficient and Secure Multiple Wireless Mesh Network 具安全性及自我組織能力的 無線網狀網路

2. 2005/7/152 Outline Introduction Background Design a Secure WMN Security Analysis Conclusion

3. 2005/7/153 Introduction (1/2) Wireless Mesh Network Properties. Security Problem. Wireless Security Problem Attacks. Secure solution.

4. 2005/7/154 Introduction (2/2) This thesis Tree topology Define the WMN ’ s basic functions Security issue Compare with other security issue

5. 2005/7/155 Wireless Mesh Network (WMN) Full & Partial mesh network. Omni directional & directional. Benefit: Reduction of install cost Large-scale depolyment (last mile) Reliability Self-management

6. 2005/7/156 WMN ’ s Architecture

7. 2005/7/157 Wireless Security Wireless Environment Open media Unlicensed ISM band Wireless Attacks Infrastructure Ad hoc

8. 2005/7/158 Wireless Attacks Infrastructure Insertion Interception and Monitoring Jamming Ad hoc Black hole Impersonation

9. 2005/7/159 Wireless Security Solutions Main Purposes Authentication Data encryption Infrastructure WEP IEEE 802.1x Ad hoc Share Key Public Key Infrastructure (PKI)

10. 2005/7/1510 WEP Wired Equivalent Privacy Integrity & Encryption Drawbacks: Key size is too small (only 40 bits) Key Sequence Reuse (Initial Vector) Message can ’ t be Authenticated

11. 2005/7/1511 IEEE 802.1x (1/2) Provide network access authentication. Supplicant, Authenticator and Authentication Server. Drawback: One-way authentication. Not protect authentication.

12. 2005/7/1512 IEEE 802.1x (2/2)

13. 2005/7/1513 Share Key Use one key to authenticate and encryption in ad hoc network. Drawbacks: Only one key Non-repudiation Key management

14. 2005/7/1514 Public Key Infrastructure Key feature of public key cryptosystem Two keys: Public Key & Private Key Computational infeasible to determine decryption key. Drawbacks Certificate Authority (CA) Spend a lot of time to en/decrypt.

15. 2005/7/1515 Outline Introduction Background Design a Secure WMN Security Analysis Conclusion

16. 2005/7/1516 The Properties of WMN Similar to ad hoc network AP should select a routing path. The routing path is always fix. Most data are sent to WG. My propose: Tree Topology.

17. 2005/7/1517 Tree Topology

18. 2005/7/1518 WMN ’ s Relationship Supplicant Authentication Agent Manage supplicants Help supplicant to authenticate. Management System Authentication server Maintain WMN

19. 2005/7/1519 Locally Secure Management Different path, different secure channel. AA only maintain his supplicants. Session key Authentication

20. 2005/7/1520 Two functions of WMN Self-Organization When a new AP joins... Self-Configuration Self-healing When a AP occurs failure … Self-reconfiguration When a AP not neighbor joins or fails …

21. 2005/7/1521 Self-Organization

22. 2005/7/1522 Trust Model Supplicant → WMN Group Key: Session key exchange first Confirm key: Authentication WMN → Supplicant WMN ’ s Public Key Signature

23. 2005/7/1523 Choose Authentication Agent Two factors Hop count Node loading 1. Choose the node has smallest hop count value. 2. If there are two nodes has equal hop count value. 1. Compare their node loading value. 2. Select the smaller one.

24. 2005/7/1524 Session Key Exchange Session key exchange first. Session key should be modified periodically. Default Key:

25. 2005/7/1525

26. 2005/7/1526 Self-Configuration (1/2) Self-Healing Determine the authentication agent fail. Start Self-Organization process.

27. 2005/7/1527 Self-configuration (2/2) Self-reconfiguration

28. 2005/7/1528 Outline Introduction Background Design a Secure WMN Security Analysis Conclusion

29. 2005/7/1529 Security Issue Message encryption: data & control Locality security Trust model Session key exchange first Period session key exchange

30. 2005/7/1530 Attacks Defense Man-in-middle (MIM) Forge AP Session Hijack Route Swindle Denial of Service (DoS)

31. 2005/7/1531 MIM & Forge AP Man-in-Middle (MIM) Use session key create secure channel. Period session key exchange. Forge AP Period session key exchange.

32. 2005/7/1532 Session Hijack Session key exchange first.

33. 2005/7/1533 Route Swindle Use signature prove node ’ s legality.

34. 2005/7/1534 Denial of Service Attack: Limited CPU and memory. Continually send streams of association and disassociation packets. Solutions: There are not any solution to solve this problem. Self-healing procedure

35. 2005/7/1535 WMN Security Comparisons

36. 2005/7/1536 Conclusion Tree based secure architecture was proposed. Define WMN ’ s basic functions of WMN. Analysis WMN ’ s security problems. Compare with other security issue.

37. 2005/7/1537 Future Work Consider more available attacks. Mobile mesh network. Other application: Sensor network Ad hoc network

38. 2005/7/1538 The End, Thank You