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具安全性及自我組織能力的 無線網狀網路. Design of Efficient and Secure Multiple Wireless Mesh Network. 研 究 生: 蔡憲邦 指導教授:柯開維 博士. Outline. Introduction Background Design a Secure WMN Security Analysis Conclusion. Introduction (1/2). Wireless Mesh Network Properties. Security Problem.
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具安全性及自我組織能力的無線網狀網路 Design of Efficient and Secure Multiple Wireless Mesh Network 研 究 生:蔡憲邦 指導教授:柯開維 博士
Outline • Introduction • Background • Design a Secure WMN • Security Analysis • Conclusion
Introduction (1/2) • Wireless Mesh Network • Properties. • Security Problem. • Wireless Security Problem • Attacks. • Secure solution.
Introduction (2/2) • This thesis • Tree topology • Define the WMN’s basic functions • Security issue • Compare with other security issue
Wireless Mesh Network (WMN) • Full & Partial mesh network. • Omni directional & directional. • Benefit: • Reduction of install cost • Large-scale depolyment (last mile) • Reliability • Self-management
Wireless Security • Wireless Environment • Open media • Unlicensed ISM band • Wireless Attacks • Infrastructure • Ad hoc
Wireless Attacks • Infrastructure • Insertion • Interception and Monitoring • Jamming • Ad hoc • Black hole • Impersonation
Main Purposes Authentication Data encryption Infrastructure WEP IEEE 802.1x Wireless Security Solutions • Ad hoc • Share Key • Public Key Infrastructure (PKI)
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
IEEE 802.1x (1/2) • Provide network access authentication. • Supplicant, Authenticator and Authentication Server. • Drawback: • One-way authentication. • Not protect authentication.
Share Key • Use one key to authenticate and encryption in ad hoc network. • Drawbacks: • Only one key • Non-repudiation • Key management
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.
Outline • Introduction • Background • Design a Secure WMN • Security Analysis • Conclusion
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.
WMN’s Relationship • Supplicant • Authentication Agent • Manage supplicants • Help supplicant to authenticate. • Management System • Authentication server • Maintain WMN
Locally Secure Management • Different path, different secure channel. • AA only maintain his supplicants. • Session key • Authentication
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…
Trust Model • Supplicant → WMN • Group Key: Session key exchange first • Confirm key: Authentication • WMN → Supplicant • WMN’s Public Key • Signature
Two factors Hop count Node loading Choose the node has smallest hop count value. If there are two nodes has equal hop count value. Compare their node loading value. Select the smaller one. Choose Authentication Agent
Session Key Exchange • Session key exchange first. • Session key should be modified periodically. • Default Key:
Self-Configuration (1/2) • Self-Healing • Determine the authentication agent fail. • Start Self-Organization process.
Self-configuration (2/2) • Self-reconfiguration
Outline • Introduction • Background • Design a Secure WMN • Security Analysis • Conclusion
Security Issue • Message encryption: data & control • Locality security • Trust model • Session key exchange first • Period session key exchange
Attacks Defense • Man-in-middle (MIM) • Forge AP • Session Hijack • Route Swindle • Denial of Service (DoS)
MIM & Forge AP • Man-in-Middle (MIM) • Use session key create secure channel. • Period session key exchange. • Forge AP • Period session key exchange.
Session Hijack • Session key exchange first.
Route Swindle • Use signature prove node’s legality.
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
Conclusion • Tree based secure architecture was proposed. • Define WMN’s basic functions of WMN. • Analysis WMN’s security problems. • Compare with other security issue.
Future Work • Consider more available attacks. • Mobile mesh network. • Other application: • Sensor network • Ad hoc network