Efficient Implementation of a Proxy-based Protocol for Data Sharing on the Cloud

In this paper, we provide a secure and efficient outsourcing scheme for multi-owner data sharing on the cloud. More in detail we consider the scenario where multiple data owners outsource their data to an untrusted cloud provider, and allow authorized users to query the resulting database, composed of the encrypted data contributed by the different owners. The scheme relies on a proxy re-encryption technique that is implemented using an El-Gamal Elliptic Curve (ECC) crypto-system. We experimentally assess the efficiency of the implementation in terms of computation time, including the key translation process, data encryption and re-encryption modules, and show that it improves over previous proposals.