Distributed Fine-Grained Access Control in Wireless Sensor Networks

In mission-critical activities, each user is allowed to access some specific, but not all, data gathered by wireless sensor networks. Yu et al~\cite{YRL09} recently proposed a centralized fine grained data access control mechanism for sensor networks, which exploits a cryptographic primitive called attribute based encryption (ABE). There is only one trusted authority to distribute keys to the sensor nodes and the users. Compromising the single authority can undermine the whole network. We propose a fully distributed access control method, which has several authorities instead of one. Each sensor has a set of attributes and each user has an access structure of attributes. A message from a sensor is encrypted such that only a user with matching set of attributes can decrypt. Compared to \cite{YRL09}, our schemes need simpler access structure which make secret key distribution more computation efficient, when user rights are modified. We prove that our scheme can tolerate compromising all but one distribution centers, which independently distribute their contributions to a single user key. Our scheme do not increase the computation and communication costs of the sensors, making it highly desirable for fine grained access control.