New Proof Techniques for DLIN-Based Adaptively Secure Attribute-Based Encryption and Their Application

We propose adaptively secure attribute-based encryption (ABE) schemes for boolean formulas over large universe attributes from the decisional linear (DLIN) assumption, which allow an arbitrary number of attribute reuse in an available formula without the previously employed redundant multiple encoding technique. Based on the key-policy (KP)ABE scheme, we have an adaptively secure communication-efficient noninteractive verifiable computation (NI-VC) from DLIN. While any previous adaptive NI-VC from a static assumption has multiplicatively dependent communication cost on the input variable multiplicity, we remove the dependency. For achieving the results, we develop a new encoding method for access policy matrix for ABE, by decoupling linear secret sharing (LSS) into its matrix and randomness, and partially randomizing the LSS shares in simulation. The new techniques are of independent interest and we expect it will find another application than ABE.