An Efficient Attribute-Based Encryption Scheme with Policy Update and File Update in Cloud Computing

Recently, more and more users and enterprises have entrusted data storage and platform construction to proxy cloud service provider (PCSP) through cloud technology. Under this background, the attribute-based encryption (ABE) mechanism is an alternative to fill the drawbacks of the traditional encryption through flexible fine-grained access policy and collusion prevention. However, there exist some security issues when the access policy and file need to be updated in practical applications. And the ABE has the problems of excessive computation and storage costs. In this article, an efficient ciphertext-policy ABE scheme with policy update and file update is proposed in cloud computing. The ciphertext components generated by first encryption can be shared when the policy update and file update happens. It reduces the storage and communication costs of the client, and the computational cost of the PCSP. Moreover, the proposed scheme is proved to be secure under the assumption of decision q-parallel bilinear Diffie-Hellman exponent (BDHE). Finally, experimental simulation shows that the proposed scheme is highly efficient in terms of policy update and file update.