Resumen
Cloud computing is a rising technology which provider an assortment of opportunities for online distribution of resources or services. The most effective advantage of using cloud computing is higher availability of services with less cost and simple scalability. While the storage space of shared data on remote servers is not a new development, current development of cloud computing validates a more careful look at its actual consequences involving privacy and confidentiality issues. As users no longer actually possess the storage of their data, traditional cryptographic primitives for the purpose of data protection cannot be directly accepted. In particular, simply downloading all the data for its integrity confirmation is not a realistic explanation due to the expensiveness in I/O and transmission cost across the network. Besides, it is often not enough to detect the data corruption only when contacting the data, as it does not offer users correctness assurance for those un-accessed information and might be too late to recover the data loss or damage. To fully make sure the data integrity and save the cloud users? calculation resources as well as online burden, it is of critical importance to allow public auditing service for cloud data, so that users may choice to an independent third party auditor (TPA) to audit the contract out data when needed. The TPA, who has expertise and abilities that users do not, can occasionally check the honesty of all the data stored in the cloud on behalf of the users, which provides a much more better and reasonable way for the users to ensure their storage rightness in the cloud. In a word, allowing public auditing services will play an important role for this emerging cloud market to become fully recognized; where users will need ways to evaluate risk and gain hope in the cloud.