Abstract: In this talk, I will present the notion of predicate encodings, an information-theoretic primitive reminiscent of linear secret-sharing that in addition, satisfies a novel notion of reusability. Using this notion, we obtain a unifying framework for adaptively-secure attribute-based encryption (ABE) schemes for a large class of predicates. Our framework relies on Waters' dual system encryption methodology (Crypto '09), and encompass the identity-based encryption scheme of Lewko and Waters (TCC '10), and the ABE scheme of Lewko et al. (Eurocrypt '10). In addition, we obtain several concrete improvements over prior works. Our work offers a novel interpretation of dual system encryption as a methodology for amplifying a one-time private-key primitive (i.e. predicate encodings) into a many-time public-key primitive (i.e. ABE). In addition, I will outline some follow-up work on proving communication complexity lower bounds for predicate encodings. Our lower bounds indicate that the known trade-offs between ciphertext and key sizes in several ABE schemes may be in fact inherent. Based on joint works with Jie Chen (ECNU), Romain Gay (ENS) and Iordanis Kerenidis (LIAFA).