Broadcast Encryption With Multiple Trust Centers and Dynamic Coalitions

Date Added: Jul 2009
Format: PDF

The authors demonstrate an extension of Hierarchical Identity-Based Encryption (HIBE) from the domain of a single Trusted Authority (TA) to a coalition of multiple independent Trusted Authorities with their own hierarchies. Coalitions formed under such schemes may be temporary or dynamic in membership without compromising security. In this paper, the authors give an instantiation with formal security model and a proof of security against selective-identity chosen-plaintext attacks in the standard model based upon the difficulty of solving the Bilinear Decisional Diffie-Hellman (BDDH) problem.