Verifiable outsourced ciphertext-policy attribute-based encryption in cloud computing

Abstract

In the attribute-based encryption (ABE) systems, users can encrypt and decrypt messages based on their attributes. Because of the flexibility of ABE, it is more and more widely used in various network environments. However, complex functionality of ABE may cause an enormous computational cost. This reason greatly restricts the application of ABE in practice. In order to minimize the local computation of ABE, we introduce the concept of verifiable outsourced ABE system, in which key generation center, encryptor and decryptor, are able to outsource their computing tasks to the corresponding service providers, respectively, to reduce the local load. In addition, they are also able to verify the correctness of outsourcing calculation efficiently by using the outsourcing verification services. This is useful to save local computational resources, especially for mobile devices. Then, we propose a specific verifiable outsourced ABE scheme and prove its adaptive security in the standard model using the dual-system encryption method. Finally, we introduce how to deploy our outsourced CP-ABE scheme in cloud computing environment.