Research on Privacy-Preserving Cloud Storage Framework Supporting Ciphertext Retrieval

Privacy security is a key issue for cloud storage. Encryption is a well established technology for protecting sensitive data. But it gives some new problems: how data owner and storage service provider to operate on encrypted data? How to reduce data owner´s workload of data management and support data sharing at the same time? If they can´t be easy to resolved, encryption will bring a lot of troubles to people. In this paper, we design a privacy-preserving cloud storage framework to solve those problems. We design an interaction protocol among participants, adopt key derivation algorithm to generate and manage keys, use the combination of symmetric and asymmetric encryption to hide the sensitive data of users, and apply Bloom filter to realize cipher text retrieval. A system based on the framework is realized. The paper analyzes the feasibility of the framework from the performance of Bloom filter, the running overhead of the system and the privacy security of the framework. Finally, we summarize our work and introduce the directions of future research.