An Associated Deletion Scheme for Multi-copy in Cloud Storage

Cloud storage reduces the cost of data storage and brings great convenience for data backup, therefore in order to improve data availability, more and more users choose to outsource personal data for multiple copies instead of storing them locally. However, multi-copy storage brings the difficulty in associating all the copies to store, increases the number of keys for encrypting every single copy and makes the integrity and the verifiable deletion of copies hard to be guaranteed, all of these issues introduce more threatens to the security of user data. In this paper, we present a cryptographic solution called ADM to solve above problems. To reduce management cost, we outsource data keys encrypted by blinded RSA to the third party, and not only to guarantee the integrity of multi-copy but also to give the verifiable evidence for deletion operation of the copies, we propose a multi-copy associated deleting solution based on pre-deleting sequence and Merkle hash tree. Finally, a proof-of-concept implementation of ADM is presented to demonstrate its practical feasibility, and we compare our scheme with other typical schemes in functionalities and conduct the security analysis and empirical performance of the prototype.