Attribute-based on-demand multicast group setup with membership anonymity

In many applications, it is desired to dynamically establish temporary multicast groups for secure message delivery. It is also often the case that the group membership information itself is sensitive and needs to be well protected. However, existing solutions either fail to address the issue of membership anonymity or do not scale well for dynamically established groups. In this paper, we propose a highly scalable solution for dynamical multicast group setup with group membership anonymity. In the proposed solution, scalability and membership anonymity are achieved via a novel design that integrates techniques such as ciphertext-policy attribute-based encryption (CP-ABE). In our design, multicast groups are specified through group member attributes. As these attributes are potentially able to be shared by unlimited number of group members, our proposed scheme scales well. Also, high level of membership anonymity is guaranteed such that every group member knows nothing but his own group membership only. The complexity of our proposed scheme in terms of computational overhead and ciphertext size is O(n), where n is the number of attributes and independent to the group size. (C) 2009 Elsevier B.V. All rights reserved.