Design of cloud storage framework with privacy-preserving

An efficient and secure framework of cloud storage is proposed to support privacy security in cloud storage. The framework adopts a multi-tree structure for indexing, designs an extirpation-based key derivation algorithm (EKDA) for key management, and constructs a discrete logarithm-based search on encrypted keyword (DLSEK) for data sharing and ciphertext retrieval. The lazy revocation is combined into the framework to deal with the changes of users' access right and dynamic operations of data. Analyzing results for the effectiveness of EKDA, the performance of DLSEK and the privacy security of the framework show that EKDA can efficiently reduce the communication and storage overheads and that DLSEK is an encryption technique which supports ciphertext retrieval and is one-way security. The proposed framework is privacy-preserving while supporting data access efficiently.