Key Technologies Of Searchable Encryption In Cloud Computing

Cloud computing is a new pattern for data service, which can provide the storage and computing resources to the public over the Internet. In the cloud computing, data owners are moving their data to the cloud server. Despite the benefits of this kind of data outsourcing, such as low-cost and flexible data access, it can also cause some privacy problems since the outsourced data may contain some sensitive information. Thus, it is necessary to encrypt the sensitive data before outsourcing them to the cloud server. Moreover, data owners would like to allow many data users to search over the encrypted data while enforcing access control policies.Searchable encryption has been recently developed as a fundamental approach to enable searching over encrypted cloud data. In the searchable encryption, the documents and the associated keywords are encrypted by data owners and outsourced to the cloud server. Search users would generate the encrypted trapdoor containing some keywords of interest to search over the dataset on the cloud server. Finally, the cloud server returns the matched results to the search user.To improve the search accuracy, the searchable encryption schemes should support multi-keyword search instead of single-keyword search. And search users would like the cloud server to return results in a specific order, so that they can obtain the more relevant results quickly. To make the searchable encryption schemes suitable for more practical scenarios, the schemes should support search authorization. Moreover, the dynamic property of the searchable encryption including index and document updating remains a challenging issue for both the searchable encryption technique.In this article, the author focuses on the authorized searchable encryption and dynamic searchable encryption in the cloud environment. Specifically, we develop an authorized and ranked multi-keyword search scheme(ARMS) and a Personalized Search scheme over encrypted data with efficient and secure Updates(PSU). The contributions of this article could be summarized as follows:By leveraging the secure k NN and ciphertext policy attribute-based encryption(CP-ABE) techniques, the authors designs a secure multi-keyword search scheme supporting result ranking and search authorization. The security analysis demonstrates that the ARMS can achieve confidentiality of documents, trapdoor unlinkability and collusion resistance. Experimental results show that the ARMS can achieve the above all functionalities and better efficiency in terms of computational overhead compared with the existing scheme.By leveraging Bloom filter and secure k-nearest neighbor technique, the author develops a versatile search scheme that supports multi-keyword search and relevance-based result ranking. By introducing the keyword preferences for mobile users and the score cleaning algorithm on the server side, the proposed PSU scheme could significantly enhance the search accuracy and improve the user search experience accordingly. Moreover, the author adopts the Third-party Auditor(TPA) in the PSU to achieve a highest security level compared with the existing proposals. The author runs the real-world experiments on a PC server and smart phones to demonstrate the efficiency of my proposed PSU scheme.