Cloud computing and storage services allow clients to move their data center and applications to centralized large data centers and thus avoid the burden of local data storage and maintenance. However, this poses new challenges related to creating secure and reliable data storage over unreliable service providers. In this study, we address the problem of ensuring the integrity of data storage in cloud computing. In particular, we consider methods for reducing the burden of generating a constant amount of metadata at the client side. By exploiting some good attributes of the bilinear group, we can devise a simple and efficient audit service for public verification of untrusted and outsourced storage, which can be important for achieving widespread deployment of cloud computing. Whereas many prior studies on ensuring remote data integrity did not consider the burden of generating verification metadata at the client side, the objective of this study is to resolve this issue. Moreover, our scheme also supports data dynamics and public verifiability. Extensive security and performance analysis shows that the proposed scheme is highly efficient and provably secure.