Achieving Dynamic Data Guarantee and Data Confidentiality of Public Auditing in Cloud Storage Service

Recently, storage as a service of cloud computing becomes a new trend to access or share files. Once files are stored in cloud, owner can access files seamlessly by personal computer or mobile device. However, owner may worry about confidentiality and integrity of owner's files stored in cloud because cloud service providers are not always trustworthy. Therefore, there are many kinds of data correctness verification methods proposed to prevent cloud service providers from cheating data owners. Among these models for auditing, bilinear pairing can achieve the most efficient way to verify data correctness and batch auditing. Although auditing methods can ensure whether data is stored properly, it is not considered that the data may be a secret data or a data owner does not want to be known by both auditors and cloud service providers. Another important issue is providing dynamic data of auditing in cloud. Wang et al.13 proposed a scheme that can provide public auditing and dynamic data, but it still cannot guarantee whether cloud has updated data honestly. For this reason, we propose a dynamic data guarantee and data confidentiality scheme for public auditing in cloud storage service.