Lightweight Secure Deduplication Based on Data Popularity

Data deduplication technology is a very important technology in cloud storage. It is widely applied in various fields, such as electronic health care. Data deduplication technology can significantly eliminate redundant data and save storage space. For protecting the security of user's data, secure deduplication schemes based on data popularity have been proposed. They use the convergent encryption to encrypt the data with high popularity and use double-layer encryption to encrypt the data with low popularity. However, these schemes have huge computational overhead because of the adopted double-layer encryption for the whole data and the complex symmetric key delivery. In order to address this problem, we design a lightweight secure deduplication scheme based on data popularity. We propose a new outer-layer encryption strategy, which encrypts two different parts of the inner-layer convergent ciphertext with different techniques. This strategy reduces the computational overhead of outer-layer encryption, while ensuring that unpopular data are still semantically secure. In addition, we use a new method to transfer the key of the outer-layer encryption. It not only reduces the computational overhead of the user to generate and encrypt the symmetric key but also reduces the computational overhead of the cloud server to decrypt the symmetric key when popularity transition arises. Finally, the experimental results demonstrate that our scheme is more efficient than the existing schemes in aspects of encrypting unpopular data and transferring the symmetric key.