Efficient public auditing scheme for non-administrator group with secure user revocation

Cloud auditing, as an important part of cloud computing, ensures file security for users. To this end, many academic authors have conducted an enormous amount of research on cloud auditing. Unfortunately, existing schemes usually involve administrators who have greater power, and malicious administrators may abuse their authority. Thus, a large number of schemes have been designed to ensure users' authority, such as implementing non-administrator groups. Whereas, it is difficult to achieve efficient user revocation in groups without administrators. This paper aims at solving the aforementioned problem. In particular, an efficient public auditing scheme is proposed with malicious users revocation and re-signature generation under the non-administrators model. First, the signature generation is executed by t users based on the threshold secret technique. Then, the proxy is responsible for aggregating t users' partial keys and signatures. Moreover, the cloud, proxy and qualified users will collaborate to generate a new partial signature through proxy re-signature when a malicious user appears. Last, we give formal security analyses and conduct a number of experiments.