Establishment of ad-hoc communities through policy-based cryptography

In [14], an ad-hoc network is perceived as a community of interconnected autonomous devices providing services and resources to each other. Such devices often belong to users from different security domains that do not have pre-existing trust relationships. A security framework is therefore needed to ensure trustworthy interactions within such kind of communities. A comprehensive policy-based security framework supporting the establishment, evolution and management of ad-hoc networks is proposed in [14]. In this paper, we first revisit the concept of policy-based encryption and describe a policybased encryption scheme from bilinear pairings. Our scheme improves the one proposed in [2] in terms of ciphertext size, while at the same time preserving the computational efficiency. Then, we leverage the framework proposed in [14] and show how a privacyenhanced secure establishment of ad-hoc communities can be achieved using the policybased encryption primitive.