Abstract: In cloud storage reliability management, a conflict occurs between the cloud storage provider (CSP) and users. The CSP considers the storage overhead as it adopts a replication mechanism to achieve data reliability. Users incur an auditing cost for verifying CSP’s reliability through remote data integrity checking. Both the CSP and users would like to spend a lower cost on the data reliability management. However, if one side decides to reduce his cost, such as, reducing stored copies for each datum, the data reliability would become lower. The opposite side would face a conflict that he has to increase his cost on the data reliability, such as, increasing auditing frequency. These conflicting situations may lead to an unsatisfied state of the data reliability if users and CSP arbitrarily make decisions according their own preferences. In this paper, we describe a game-theoretic analysis to design optimal strategies for users and the CSP. We present two cases of the user-CSP game: the strategic game and Bayesian game. We determine the Nash Equilibrium (NE) and Bayesian Nash Equilibrium (BNE) to get stable solutions for these games. In the numerical study, we use the pricing strategy adopted by Amazon S3 to explain our analysis. We analyze the effect of the parameter setting with replica number n, data sensitive level, and punishment on the NE and BNE. Our results show that if a user wants to store important data in the CSP, he should choose the Audit strategy for 1.0⩽n⩽2.1 in the mild punishment and 1.2⩽n⩽2.2 in the severe punishment. According to these results, a user can determine whether to pay for auditing by the pricing tags, and the CSP can formulate appropriate policies for reliability of storage.
Keywords: Cloud storage, data reliability, game theory, provable data possession, public cloud data auditing
