International Association
for Cryptologic Research

We develop a technique inspired by pseudorandom functions that allows us to increase the entropy available for proving the security of dual system encryption schemes under the Decisional Linear Assumption. We show an application of the tool to Attribute-Based Encryption by presenting a Key-Policy ABE scheme that exhibits a significant improvement over the state of the art schemes in public parameter size in terms of the number of reuses of attributes allowed in the policy while remaining fully secure under the Decisional Linear Assumption.