Abstract:In order to solve the problem of low audit efficiency due to the use of power exponent, bilinear mapping, point hash mapping and other expensive operations in the existing certificateless cloud auditing scheme, an efficient certificateless cloud auditing scheme was designed in this paper. In the key generation stage, combined with the certificateless signature technology, the user’s public and private keys were generated by the key generating center (KGC) in cooperation with the user, so that the strong dependence of auditing system security on KGC security was avoided. Consequently, the shortcomings of complex public key certificate management under the public key infrastructure (PKI) system and the inherent key escrow issues under the identity-based cloud audit scheme were solved. In the data preprocessing stage, the data was encrypted and divided into blocks. Therefore, the data content privacy was protected and the calculation and communication overhead of the scheme was reduced. In the data dynamic update stage, the virtual index data structure was used to realize the insertion, deletion and modification of data blocks. As a result, the extra computational overhead caused by label recalculation was avoided. In the data auditing stage, the task of users to verify the integrity evidence was replaced by a third party auditor (TPA), which reduces the user’s computational burden. In the section of security analysis, it was proved that the substitution attack from the cloud was resisted, the privacy protection was achieved, and the forgery attacks by two types of adversaries were resisted. In the performance analysis part, numerical analysis and comparison of the proposed scheme with the existing schemes were carried out on the JPBC library. The experiments show that the proposed scheme significantly reduces the computational cost.