A Secret and Traceable Approach for Cloud Data Sharing

With the development of cloud computing, data owners generally use cloud services to reduce storage and computing overhead. However, data stored in cloud servers is out of the direct control of the data owners, causing serious security issues. Access control mechanism based on cryptography can effectively protect the security of cloud data and prevent unauthorized access to it. Nevertheless, users may redistribute data to other users after obtaining it, which can harm the copyright interests of the data owner. To address this issue, this paper proposes a secret and traceable approach for cloud data sharing. We combine the lattice-based proxy re-encryption with digital watermarking technology for redistribution tracking in cloud data sharing scenario. The lattice cipher used in this scheme is an encryption algorithm with homomorphic property based on the Ring-LWE problem. It has the advantage of reducing the ciphertext length and improving the efficiency of encryption. This paper demonstrates the feasibility and effectiveness of this scheme from a series of experiments. The encryption of an image of size 1024*1024 pixels takes only 9.78 seconds on average. The computational performance of this scheme is roughly 91.434% better than the existing data sharing schemes supporting redistribution tracking.