Identity-based remote data possession checking in public clouds

Checking remote data possession is of crucial importance in public cloud storage. It enables the users to check that their outsourced data have been kept intact without downloading the original data. The existing remote data possession checking (RDPC) protocols have been designed in the PKI (public key infrastructure) setting. The cloud server has to validate the users’ certificates before storing the data uploaded by the users in order to prevent spam. This incurs considerable costs since numerous users may frequently upload data to the cloud server. This paper addresses this problem with a new model of identity-based RDPC (ID-RDPC) protocols. We present the first ID-RDPC protocol proven to be secure assuming the hardness of the standard computational Diffie-Hellman (CDH) problem. In addition to the structural advantage of elimination of certificate management and verification, our ID-RDPC protocol also outperforms existing RDPC protocols in the PKI setting in terms of computation and communication.