Generic Constructions of Server-Aided Revocable ABE with Verifiable Transformation

Attribute-based encryption (ABE) is a promising approach in cloud computing services to enable scalable access control on encrypted data. Server-aided revocable attribute-based encryption (SR-ABE) was proposed to realize user revocation and optimize the workloads of data users in ABE. In this paper, we revisit the notion of SR-ABE and present a generic construction of verifiable SR-ABE, which can not only transform a revocable attribute-based encryption (RABE) scheme into an SR-ABE scheme but also provide verifiability to check whether the server behaves as expected. We additionally give an instantiation of verifiable SR-ABE by applying the generic construction on a concrete revocable ABE scheme, and evaluate the performance of the instantiation in terms of functionality, storage overhead, computational cost, and security.