Replicated Data Integrity Verification in Cloud
Cloud computing is an emerging model in which computing infrastructure resources are provided as a service over the Internet. Data owners can outsource their data by remotely storing them in the cloud and enjoy on-demand high quality applications and services from a shared pool of configurable com- puting resources. However, since data owners and cloud servers are not in the same trusted domain, the outsourced data may be at risk as the cloud server may no longer be fully trusted. Therefore, data integrity is of critical importance in such a scenario. Cloud should let either the owners or a trusted third party to audit their data storage without demanding a local copy of the data from owners. Replicating data on cloud servers across multiple data centers provides a higher level of scalability, availability, and durability. When the data owners ask the Cloud Service Provider (CSP) to replicate data at different servers, they are charged a higher fee by the CSP. Therefore, the data owners need to be strongly convinced that the CSP is storing all the data copies that are agreed upon in the service level contract, and the data-update requests issued by the customers have been correctly executed on all the remotely stored copies. To deal with such problems, previous multi copy verification schemes either focused on static files or incurred huge update costs in a dynamic file scenario. In this paper, we propose some ideas under a Dynamic Multi-Replica Provable Data Possession scheme (DMR-PDP) that prevents the CSP from cheating; for example, by maintaining fewer copies than paid for. DMR-PDP also supports efficient dynamic operations like block modification, insertion and deletion on data replicas over cloud servers.