[Wat11] Ciphertext-Policy Attribute-Based Encryption: An Expressive, Efficient, and Provably Secure Realization

Authors: Brent Waters | Venue: PKC 2011 | Source

Abstract

We present a new construction of ciphertext-policy attribute-based encryption (CP-ABE) that is both expressive and provably secure under a standard complexity assumption. Our scheme supports any access policy that can be expressed as a monotone Boolean formula over a polynomial number of attributes. The scheme achieves selective security under the Decisional Bilinear Diffie-Hellman (DBDH) assumption in the standard model. Prior to this work, the only CP-ABE scheme with a rigorous security proof (BSW07) was proved secure in the generic group model. Our construction introduces a water-marking technique for embedding challenge attributes into the public parameters, enabling a tight reduction to the DBDH assumption and providing the first CP-ABE scheme with a full, standard-model proof of selective security.