Adaptive Trust Management in MANET

In MANET, trust management is an effective measure of interoperation and collaboration. The authorization decisions to collaborate with a stranger are often tackled by two different trust management systems: a policy-based approach, where authorization decisions are built on logical rules and verifiable properties encoded in signed credentials, and a reputation-based approach, based on collecting, aggregating and disseminating reputation among the principals. However, the overhead caused by proof of compliance on authorization and the un-availability caused by lack of evidence to make decision may negate the strong and objective security advantages of policy-based approach, whilst vagueness, complexity and inaccurate characterization caused by reputation evolution may eliminate the quantitative and flexible advantages of reputation-based approach. Actually an integrated approach would enhance significantly trust management systems. We integrate the notion of policy proof and reputation evolution into trust management such that the decision process is aware of not only the strong and objective security implications, but also the calculability and the availability security implications. Finally, a trust management framework that incorporates trust is presented.