Availability Based Trust Model of Clusters for MANET

1. Availability Based Trust Model of Clusters for MANET Key Laboratory for Information System Security of Ministry of Education, Tsinghua University

2. 1. Introduction 2. Related Work 3. Availability Based Trust Model 4. Trust Computation of Cluster 5. Conclusion Content

3. 1. Introduction 2. Related Work 3. Availability Based Trust Model 4. Trust Computation of Cluster 5. Conclusion Content

4. Introduction of MANET • Mobile Ad Hoc Network(MANET) sometimes called a mobile mesh network, is a self-configuring network of mobile devices connected by wireless links.

5. MANETProblems • MANET is particularly suitable in the environment which lacks of infrastructure to build a temporary wireless application , mainly used in military, emergency rescue and civil operations, and has become a research hotspot. • MANETcharacteristics • No infrastructure • Multi-hop network • Dynamic topology • Resource constraint • Those characteristics lead to an urgent need for the security of the MANET network

6. MANET Security Mechanism Research • Proposed security mechanism for MANET • Based on Distributed Centre Key Management Scheme(DCA) • Based on Certificate Chain Key Management Scheme (CC) • Trust-based Security Management Solution • …… • Traditional PKI programs focus mostly concentrated in the confidentiality , and integrity on the availability is considered insufficient. • Trust-based safety programs can play a role in the availability of protection, but not proposed for the availability of the trust model.

7. Summary • MANET ’s characteristics which is no infrastructure, multi-hop network, dynamic topology, and resource constraint lead to an urgent need for the security. • At present, many MANET security solutions has been proposed, but the consideration for availability is insufficient. • The establishment of the trust model for usability, and applied to routing protocols.

8. 1. Introduction 2. Related Work 3. Availability Based Trust Model 4. Trust Computation of Cluster 5. Conclusion Content

9. Related research categories • At present, domestic and foreign made many security mechanism for MANET, in accordance with the deployment of security mechanisms can be divided into two broad categories: • Pre-configuration security mechanism • DCA: Distribute Certificate Authority • Improvement of DCA • security mechanism of self-organized • CC: Certificate Chain • Trust model safety program • Distributed trust model • Experience and probability statistics based trust model • Subjective logic modeling • Vector trust model

10. Related research——DCA • The core idea of DCA is to distribute all or part of the trusted certificate authority functions in the traditional wired network to the pre-configured nodes of multiple networks. Then these nodes will provide security service to the network customers. • Problems ： • DCA network nodes need to act as pre-configured, it is difficult to meet the dynamic nature of MANET and temporary network requirements; • Because the need for pre-deployment, DCA current MANET network segmentation for not very effective solution, the situation appears CA is not complete, can not guarantee the availability of MANET networks; • For resource-constrained MANET environment, the distributed threshold-based certification program for causing excessive network communication overhead, but also affect the network availability.

11. Related research——CC • CC was required for DCA shortcomings of pre-configured security mechanisms proposed, and its main idea is to pass through the certificate chain to build the network trust. • Problems: • Efficiency: When more nodes in the network, each node needs to maintain a huge certificate graph, and also to the ongoing public-key operation, which means that CC can not cope with large-scale network applications; • CC certification is based on close contact in exchange for trust relationship established: two nodes of the certificate exchange channel through additional credibility and build on the exchange of certificates based on close contact of both. But in the MANET network, most nodes are unknown, the trust relationship between nodes can not simply built on the basis of close contact.

12. Related research—Distributed trust model • Distributed trust model, Abdul-Rahman and other people start from the basic concept of trust, suggesting a kind of trust model for opening network environment. The biggest contribution of this model is that it is the first time to divide trust relationship into direct trust and recommended trust and the subcategories of this trust relationship are widely accepted. In addition, this model adopts a series of discrete values to measure trust relationship and the delivery method of trust degree is given, but there is no integrated method of giving trust. • Problems: • Not given integrated method of giving trust.

13. Related research——Experience and probability statistics based trust model • Experience and probability statistics based trust model is proposed by Beth, who introduced the concept of experience to express and measure trust and to use methods of probability and statistics, given the transfer of trust and comprehensive formula. • Problems: • Lack of trust in subjective considerations.

14. Related research—Subjective logic modeling • Subjective logic modeling is proposed by Jøsang and other people. They use the subjective logic to build the model, describe and measure the trust relationship by introducing the concept of space of fact and space of idea. It includes the uncertain judgment of something happened and provides a set of subjective logic operators for the derivation of trust degree and composite calculation. • Problems: • Mainly used for e-commerce.

15. Related research——Vector trust model • Vector trust model is proposed by Indrajit and other people who use vector to describe the trust relationship. It emphasizes that trust must exist in some specific contexts. This model is mainly relying on three parameters: experience, knowledge and recommendation. Based on these three parameters, we can get the quantitative denotation of trust. Comparing with subjective logic modeling, vector trust model is more suitable for the MANET environment. • Problems: • Its consideration towards MANET availability is not enough.

16. 1. Introduction 2. Related Work 3. Availability Based Trust Model 4. Trust Computation of Cluster 5. Conclusion Content

17. Analysis of MANET Availability • The most easily achieved and at the same time the most devastating attack in MANET is attacks against the availability. such as black hole attacks, DOS attacks. And as a special and temporary assignments for the network, especially for some of the contingency environment, MANET availability is extremely important. • key parameters of MANET availability • Honest collaboration • Only with the collaborated ability of network nodes can the connection of network be guaranteed to achieve the availability of MANET. • ability • There are diversities existing in various nodes in MANET so the capable ones are always busy. It not only increases the network efficiency, but also reduces the resource consumption of the weak nodes so that improves the overall network availability.

18. The Establishment of Availability Trust Model • Security trust: the security trust of MANET is the trust of node can response the request promptly, correctly answer promptly, deliver and transfer the data pack promptly to node .

19. Establishment of Security Trust • Honest assessment of the main objectives of the trust in collaboration is to determine the credibility of the node, to encourage honest and cooperative behavior of nodes to exclude malicious nodes. • This paper considers collaborative trust the honesty of the node should include three aspects: • Safety behavior trust • Negative trust • Experience trust

20. Safety behavior trust • Safety behavior trust is a node of the target node, the trust has complied with the network behavior.

21. Negative trust • Negative trust is due to the malicious behavior of malicious nodes in the network that produces negative.

22. Experience trust • experience trust means the experience of some certain trusted nodes in the network creates the trust. • If in the below formula represents experience trust, then • Since experience trust is the trust produced by safety behavior trust and negative trust, and it varies according to both, their relationship is as below formula:

23. 诚实协作信任的计算 • And the security trust can be formalized as: • This paper suggests the following pre-assessment formula of security trust:

24. The Establishment of Ability Trust • Ability trust mainly means the extent of ability capacity of some certain nodes which participate in the web collaboration to create trust.

25. Trust Calculation of ABTM • Model Assumption:

26. Integrated Calculation of Trust Model

27. Integrated Calculation of Trust Model

28. 1. Introduction 2. Related Work 3. Availability Based Trust Model 4. Trust Computation of Cluster 5. Conclusion Content

30. 1. Introduction 2. Related Work 3. Availability Based Trust Model 4. Trust Computation of Cluster 5. Conclusion Content

31. Conclusion • Based on the analysis of availability related factors in MANET, we present an availability based trust model in this paper. Furthermore, a cluster based trust model (ABTMC，Availability Based Trust Model of Clusters) is presented with the consideration with the resource constrain of node, dynamic topology, and the unbalance of computing capability and resource capability among MANET nodes. Many availability oriented security service can be obtained based on this model.

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