A Context-Aware Access Control Model for Pervasive Environments

Pervasive environments are dynamically changing environments with enormous amounts of information available for access from anywhere. This paper presents a framework for context-aware access control using threshold cryptography (CAAC-TC) where the administration of access control is distributed between different context services. CAAC-TC encrypts information using threshold cryptography where the private key is split up between the different context conditions which must be captured or realized. The idea here is that not all specified context conditions must be captured, k captured contexts are enough. The management of access decisions is distributed among the different contexts. In CAAC-TC, multiple encryption layers can be specified where each layer is an encryption scheme of either n-out-of-n or k-out-of-n. Multiple layers simulate the use of an `AND´ operator. Some of the main characteristics of CAAC-TC are: decentralization, context error tolerant (distributed trust), extensibility, flexibility and scalability.