Privacy-Preserving Public Auditing for Dynamic Group Based on Hierarchical Tree

As the rapid development of cloud storage, it is important to protect the security of shared data in cloud. Therefore, it is necessary to protect users’ privacy and verify the integrity of data efficiently during the data sharing. As the existing schemes consider little about the management and secure distribution of key, based on hierarchy tree and proxy re-signature, a privacy-preserving public auditing scheme which supports dynamic group in cloud storage is supposed. The proposed scheme firstly uses logical hierarchy key tree to establish and distribute keys, and a key server is utilized to store keys. The revocation of user is independent from users’ obtaining new group secret key as each user only stores the leaf node key. When a user revokes, the valid user can obtain the new group secret key with their original keys. Therefore, the scheme is more efficient for dynamic group. The security analysis and performance analysis show that the scheme is secure and efficient.