Research On Comparable Encryption Based On Sliding Window Method And Its Application

With the rapid development of cloud computing, outsourcing data to cloud server for storage becomes an attractive trend. More and more users outsource their data to a cloud server, a cloud server is responsible for managing the data user stored, and providing services user needed. By this way, users do not need to manage software and maintain hardware, they just need to assign tasks to cloud server without considering the limited local resources. However, there is much sensitive information in their data and a cloud server is not always fully trusted by users, this brings security risks to users while a cloud server bringing conveniences to users. To protect the confidentiality of the data stored by users, data should be encrypted before uploaded to a cloud server. But, how to query on ciphertexts becomes a new challenge in cloud computing security. Comparable encryption provides a solution to compare two encrypted numbers, it can get the relation of these two numbers by accompanying token information while encrypting. But the ciphertexts and tokens are generated bit by bit, which leads to a high computation and storage workload. In this paper, we study and analysis on the existed encryption schemes, briefly describe the research status of the existed schemes and then propose an efficient comparable encryption scheme based on sliding window method. The main works of this paper are as follows:1. Propose an efficient comparable encryption scheme based on sliding window method. Reduce the computation and storage workload in comparable encryption scheme and promote its efficiency. This make it better fit in the work of querying on ciphertexts in database system under cloud environment.2. Analyze our scheme on security and efficiency, point out our advantages compared to the original scheme. A user can achieve variable trade-off between security and efficiency through adaptively setting the window size.3. Realize our scheme by using ASP.NET technique, apply it in the database we created and can get the right results after querying. It is showed in the application that our scheme could protect the score information of students.