The emergence of cloud storage has solved many pain points of the traditional storage model. However, the issue of cloud storage data integrity - whether the cloud storage provider has kept the data intact - has raised concerns about cloud storage. Integrity auditing of cloud storage data allows users to know the integrity of the outsourced data without downloading it in its entirety. However it is not enough to know its integrity. Multi-replicas, as a common means of redundancy, improves the reliability of cloud storage data. And storing multi-replicas on multi-cloud storage providers (CSPs) enhances this feature. In a multi-replica multi-CSPs scenario, if the independence of CSPs is given full play and auditing is performed among CSPs, not only the introduction of third party auditor (TPA) can be eliminated, but also the tag generation, which is a huge computational overhead, can be removed. Inspired by this, in this paper we propose a new model for remote data integrity auditing: CIA (Collaborative Integrity Auditing). In addition to the reduction in computational overhead, the proposed scheme provides unprecedented support for free data blocking. The proposed scheme employs only hash functions in the calculation, which has a negligible computational overhead compared to the traditional bilinear pairing-based schemes. Theoretical analysis and experimental results show that the proposed scheme provides high efficiency and flexibility with security assurance, and can be used as a lightweight alternative to traditional remote data integrity auditing schemes in multi-replica multi-CSP scenarios.

ABSTRACT With the development of the Internet, multiplayer online games are rapidly replacing the traditional single‐player games. The peer‐to‐peer architecture, which is suitable for massive multiplayer online games, is being considered as the replacement for traditional client–server architecture. Because the current solutions cannot prevent the cheating problems to gain unfair advantages in these games completely, we summarize the problems existing in some event signature protocols for peer‐to‐peer online games and propose a new secure event signature protocol. The security basis of the proposed protocol is the discrete logarithms and bilinear pairing. Our protocol provides higher security than some current protocols on secure event signature, although the efficiency of our protocol is lower than theirs. Copyright © 2012 John Wiley & Sons, Ltd.