A novel privacy preserving keyword searching for cloud storage

In cloud storage environment, clients no longer have physical possession of their data, it indicates that their data may be leaked maliciously by cloud provider. To avoid the security risks, we propose a privacy preserving keyword searching scheme whose encryption procedure needs no pairing operation. Our scheme allows users to encrypt their data before uploading to the cloud, and retrieve them by searching the encrypted keywords, besides it enables the cloud service provider to participate in decipherment which reduces the computational overhead of the client´s decryption. Performance analysis shows our new scheme is more efficient and more adaptable to the cloud environment than the existing schemes. In addition, the new scheme is proved to be semantically secure in the random oracle model.