Panda Public Auditing for Shared Data with Efficient User Revocation

Abstract

With public audit ability, a trusted entity with expertise and capabilities that data owners do not possess can be delegated as an external audit party to assess the risk of outsourced data when needed. Such an auditing service not only helps save data owner’s computation resources but also provides a transparent yet cost-effective method for data owners to gain trust in the cloud for all types of users who require the secure transmission or storage of data in any kind of media or network. In this project, focus is on addressing data privacy issues using Searchable symmetric encryption and formulation of the privacy issue from the aspect of similarity relevance and scheme robustness. To eliminate the leakage, propose a two-round searchable encryption scheme that supports Data multi keyword retrieval. In two-round searchable encryption, two methods are employed, a vector space model and homomorphic encryption. The vector space model helps to provide sufficient search accuracy. The homomorphic encryption enables users to involve in the ranking while the majority of computing work is done on the server side by operations only on cipher text.

Existing System

Provable Data Possession (PDP), first proposed by Ateniese, allows a public verifier to check the correctness of a client’s data stored at an untrusted server. By utilizing RSA-based homomorphic authenticators and sampling strategies, the verifier is able to publicly audit the integrity of data without retrieving the entire data, which is referred to as public verifiability or public auditing. Shacham and Waters designed an improved PDP scheme based on BLS (Boneh-Lynn-Shacham) signatures. To support dynamic operations on data during auditing, presented another PDP mechanism based on symmetric keys. However, it is not publicly verifiable and only provides a user with a limited number of verification requests.

Proposed System

Based on the new proxy re-signature scheme and its properties in the previous section, a new mechanism is introduced, Panda is a public auditing mechanism for shared data with efficient user revocation. In this mechanism, the original user acts as the group manager, who is able to revoke users from the group when it is necessary. Meanwhile, the cloud is allowed to perform as the semi-trusted proxy and translate signatures for users in the group with resigning keys. As emphasized in recent work, for security reasons, it is necessary for the cloud service providers to storage data and keys separately on different servers inside the cloud in practice. Therefore, in this mechanism, it’s assumed the cloud has a server to store shared data, and has another server to manage resigning keys. To ensure the privacy of cloud shared data at the same time, additional mechanisms, such as, can be utilized. The details of preserving data privacy are out of scope of this paper. The main focus of this paper is to audit the integrity of cloud shared data.

Architecture