Proxy Provable Data Possession with General Access Structure in Public Clouds

Since public clouds are untrusted by many consumers, it is important to check whether their remote data keeps intact. Sometimes, it is necessary for many clients to cooperate to store their data in the public clouds. For example, a file needs many clients' approval before it is stored in the public clouds. Specially, different files need different client subsets' approval. After that, these stored remote data will be proved possession by the verifier. In some cases, the verifier has no ability to perform remote data possession proof, for example, the verifier is in the battlefield because of the war. It will delegate this task to its proxy. In this paper, we propose the concept of proxy provable data possession PPDP which supports a general access structure. We propose the corresponding system model, security model and a concrete PPDP protocol from n-multilinear map. Our concrete PPDP protocol is provably secure and efficient by security analysis and performance analysis. Since our proposed PPDP protocol supports the general access structure, only the clients of an authorized subset can cooperate to store the massive data to PCS Public Cloud Servers, and it is impossible for those of an unauthorized subset to store the data to PCS.