Secure pervasive social networking based on multi-dimensional trust levels

Mobile Ad Hoc Network (MANET) is becoming a generic platform for pervasive social networking (PSN). It is important to secure communications in PSN for crucial instant social activities. However, both centralized and distributed security solutions for PSN are impractical due to the lack of connection to a central party in urgent situations or heavy traffic and processing load for key management that is caused by the dynamic changes of PSN topology and node trust. Applying pseudonyms for PSN nodes exacerbates this situation. How to automatically control data access in a secure and efficient way is a challenge. For effectively securing PSN, the following two fundamental requirements have to be met: 1) Controlling data access should be based on trust relationships and must be flexible; 2) Key management should be done with sufficiently low computation and communication cost. In this paper, we utilize two dimensions of trust levels either evaluated by a trusted server or individual PSN nodes or both to control PSN data access in a heterogeneous manner on the basis of attribute-based encryption (ABE). We formally prove the security of our scheme based on the security of a distributed ABE scheme by Müller et al. and analyze its performance and computational complexity. Extensive analysis shows that our proposed scheme is highly efficient and provably secure under relevant system and security models.