An efficient public-key attribute-based broadcast encryption scheme allowing arbitrary access policies

We describe a new public-key and provably secure attribute-based broadcast encryption scheme which supports complex access policies with AND, OR and NOT gates. Our scheme, especially targetting the implemention of efficient Pay-TV systems, can handle conjunctions of disjunctions by construction and disjunctions of conjunctions by concatenation, which are the most general forms of Boolean expressions. It is based on a modification of the Boneh-Gentry-Waters broadcast encryption scheme in order to achieve attribute collusion resistance and to support complex Boolean access policies. The security of our scheme is proven in the generic model of groups with pairings. Finally, we compare our scheme to several other Attribute-based Broadcast Encryption designs, both in terms of bandwidth requirements and implementation costs.