2. 1 APPLICATION OF DDDAS FOR TRUSTED COMMUNICATION IN MOBILE NETWORKS. Onolaja Olufunmilola Supervisors: Dr Rami Bahsoon, Dr Georgios Theodoropoulos

3. 2 Overview of presentation DDDAS Motivation Trust in mobile networks Reputation Systems Previous work Contribution Conclusion

4. 3 What is DDDAS? DDDAS (Dynamic Data-Driven Application Systems) is a paradigm whereby applications (or simulations) and measurements become a symbiotic feedback control system. This paradigm entails the ability to dynamically incorporate additional data into an executing application, and in reverse, the ability of an application to dynamically steer the measurement process. [4]

5. 4 Motivation The dynamic nature of mobile networks raises the issue of how connected mobile devices can be trusted. Mobile networks have been plagued with many security issues resulting in threats from compromised nodes inside the network. Despite the existing security paradigms, the assurance of security with the exposure of new mobile generation still remains a problem.

6. 5 Objective The objective of this research is to apply the concept of DDDAS to build reputation systems to address the security problems related to trust in mobile networks.

7. 6 Trust and Reputation In the context of networks, when a node is trusted, it implicitly means that the probability that it will perform an action that is beneficial or at least not detrimental in the network is high enough to consider engaging in some form of cooperation with the node. Reputation on the other hand, is the opinion of an entity about another, it is the trustworthiness of a node.

8. 7 Goals of Reputation Systems Provide information that allows nodes to distinguish between trustworthy and non-trustworthy nodes; Encourage nodes to be trustworthy; Discourage participation of nodes that are untrustworthy; Isolating misbehaving nodes and denying them service. [5,6]

9. 8 Previous Work  Reputation in the CORE [2] (A Collaborative Reputation Mechanism to enforce node cooperation in Mobile Ad hoc Networks) approach is formed and updated along time through direct observations and through information provided by other members of the community.  CONFIDANT [3] (Cooperation Of Nodes – Fairness In Dynamic Ad hoc NeTworks) reputation based system is a distributed, symmetric reputation model which uses both first and second hand information from direct neighbours/ other members for updating reputation values.

10. 9 Drawbacks There is heavy reliance on information provided by other nodes within the network making it difficult to detect and problems when there are cooperated misbehaviour between nodes within the network; The consideration of ratings of other nodes gives room for false accusations/praise within the system; Provide a method of updating reputation values which may not meet the requirement of such dynamic environments.

11. 10 Contribution Collaborative attack is a pending problem and this research aims to address it through a combination of centralised and decentralised approaches to information gathering. The paradigm will be applied to dynamically measure trust levels, to determine the reputation of each node.The simulation will continually incorporate new measurements at runtime for the system to accurately determine and update the trust values.

12. 11 Contribution High level Architecture

13. 12 Contribution By comparing the archived reputation score of a mobile device and with its online behaviour, malicious/rouge devices may be detected and exclude. It is assumed that the behaviour of an unauthorized mobile device will be different from the expected. However, nodes may actually behave as expected to gain good reputation before causing undesirable results. This is where the run time dynamic changes in reputation scores becomes useful.

14. 13 Summary This approach will be evaluated in terms of its effectiveness in achieving a better overall security through analysis and simulations. Finally, the aim is to show that DDDAS is a potential paradigm for addressing security problems by providing trusted communication in mobile ad-hoc networks.

15. Questions? If there are any …. If there are any ….

16. 15 References [1] D. Gambetta. Can We Trust Trust?. In, Trust: Making and Breaking Cooperative Relations, Gambetta, D (ed.). Basil Blackwell. Oxford, 1990, pp. 213-237. [2] P. Michiardi and R. Molva, “ Core: A Collaborative Reputation Mechanism to Enforce Node Cooperation in Mobile Ad Hoc Networks, ” Commun. and Multimedia Security 2002 Conf., Portoroz, Slovenia, Sept. 26 – 27 2002. [3] S. Buchegger and J. Le Boudec. A robust reputation system for P2P and mobile ad-hoc networks. In Proceedings of P2PEcon 2004, Harvard University, Cambridge MA, U.S.A., June 2004 [4] Douglas, C. (2006), “ Dynamic Data Driven Application Systems", www.dddas.org [accessed 20 Jan 2009]. [5] P. Resnick and R. Zeckhauser. Trust among strangers in internet transactions: Empirical analysis of ebays reputation system. Working Paper for the NBER workshop on empirical studies of electronic commerce, 2001. [6] Sonja Buchegger and Jean-Yves Le Boudec. Self-policing mobile ad hoc networks by reputation systems. IEEE Communications Magazine, 43(7):101-107, 2005. [7] Srinivasan A., Teitelbaum J., Liang H., WU J., Cardei M. Reputation and Trust-based systems for Ad Hoc and Sensor Networks.