Application Of Third-Party Auditor In Cloud Stroage Data Integrity Verification

With the rapid development of information technology, the requirements for data processing and storage are.increasing. Traditional storage mode can’t adapt this new challenge. With the properties of low cost, advanced technology and efficient business model, cloud storage has been concerned after its appearance, and has been made a rapid development. But as a new storage model, users concern and worry about the security of cloud storage particularly. Therefore, under the premise to satisfy user’s storage needs, how to ensure the correctness and integrity of storage data is a key issue in the development and popularization of cloud storage technology.As an important cloud storage verification technology, data integrity is the direction of this thesis. We focus on the application and implementation of third-party auditor in data integrity verification. The main purpose of data integrity verification mechanism is to verify the correctness and integrity of data stored in the cloud server, whether the data has been modified maliciously or deleted. Sometimes users for some reasons are unable to verify the data integrity and need to delegate verification power to third-party auditor. Third-party auditor relieves users’ pressure of data integrity verification, but also increases the potential security problems.This thsis analyzes the general system model of data integrity verification. Based on existing data integrity verification scheme, we design and implement two data integrity verification schemes using third-party auditor. The main contents of this thsis are:(1) a new Provable Data Possession based on partial delegation (PDPDP) is proposed. The PDPDP system model and security model are based on bilinear pairing and partial delegation. The major feature of the proposed scheme is:the Client can delegate verification power to the proxy by sharing with the proxy the converted secret key and can revoke or delete the proxy in an easy way at any time. Compared with existing data integrity verification schemes, the proposed scheme has less computation overhead with the same level of security and also has wider application scenarios.(2) a public auditing scheme supporting group is proposed. In this scheme, both individual users and group users can resort a third-party auditor to check the integrity of outsourced data. This scheme can ensure the correctness of data integrity verification, and third-party auditor can perform audit for multiple group users simultaneously and efficiently. By utilizing the idea of proxy re-signatures, the scheme supports efficient group users’ revocation. In addition, privacy-preserving is satisfied in this scheme.(3) Extensive security analyses show these schemes are provable secure in random oracle. Estimating the cost of basic cryptographic and analyzing the experiment show these proposed schemes are highly efficient and practical.