Cloud computing moves the application software and databases to the centralized large data centers, where the management of the data and services may not be fully trustworthy. In this paper, they study the problem of ensuring the integrity of data storage in cloud computing. To reduce the computational cost at user side during the integrity verification of their data, the notion of public verifiability has been proposed. However, the challenge is that the computational burden is too huge for the users with resource-constrained devices to compute the public authentication tags of file blocks.