Efficient Client-Side De-duplication of Encrypted Data with Public Auditing in Cloud Storage
At present, there is a considerable increase in the amount of data stored in storage services, along with dramatic evolution of networking techniques. In storage services with huge data, the storage servers may want to reduce the volume of stored data, and the clients may want to monitor the integrity of their data with a low cost, since the cost of the functions related to data storage increase in proportion to the size of the data. To achieve these goals, secure deduplication and integrity auditing delegation techniques have been studied, which can reduce the volume of data stored in storage by eliminating duplicated copies and permit clients to efficiently verify the integrity of stored files by delegating costly operations to a trusted party, respectively. So far many studies have been conducted on each topic, separately, whereas relatively few combined schemes, which support the two functions simultaneously, have been researched. In this paper, we design a combined technique, which performs both secure deduplication of encrypted data and public integrity auditing of data. To support the two functions, the proposed scheme performs challenge-response protocols using the BLS signature-based homomorphic linear authenticator. We utilize a third party auditor for performing public audit, in order to help low-powered clients. The proposed scheme satisfies all the fundamental security requirements. We also propose two variances that provide higher security and better performance.
Larger volumes of data require higher cost for managing the various aspects of data, since the size of data influences the cost for cloud storage services. The scale of storage should be increased according to the quantity of data to be stored. In this viewpoint, it is desirable for storage servers to reduce the volume of data, since they can increase their profit by reducing the cost for maintaining storage. On the other hand, clients are mainly interested in the integrity of their data stored in the storage maintained by service providers. To verify the integrity of stored files, clients need to perform costly operations, whose complexity increases in proportion to the size of data. In this viewpoint, clients may want to verify the integrity with a low cost regardless of the size of data. Owing to the demands of storage servers and clients, many researches on this topic are available in the literature.
• Vulnerable to internal and external security threats.
• Weak servers may try to hide the fact that they lost some data, which were entrusted by their clients.
• Servers delete rarely accessed users data in order to increase the profit.
In this work , we design a new scheme for secure and efficient cloud storage service. The scheme supports both secure deduplication and integrity auditing in a cloud environment. In particular, the proposed scheme provides secure deduplication of encrypted data. Our scheme performs PoW for secure deduplication and integrity auditing based on the homomorphic linear authenticator (HLA), which is designed using BLS signature. The proposed scheme also supports
public auditing using a TPA (Third Party Auditor) to help low-powered clients. The proposed scheme satisfies all fundamental security requirements, and is more efficient than the existing schemes that are designed to support deduplication and public auditing at the same time. The main improvement in this paper is that we propose two variations to provide higher security and better performance. In the first variance, which is designed for stronger security, we assume a stronger adversary and provide a counter measure against the adversary. In the second variance, we design a technique that supports a very low-powered client and entrusts more computation to the cloud storage server in the upload procedure.
When storing data on remote cloud storages, users want to be assured that their outsourced data are maintained accurately in the remote storage without being corrupted. In addition, cloud servers want to use their storage more efficiently. To satisfy both the requirements, we proposed a scheme to achieve both secure deduplication and integrity auditing in a cloud environment. To prevent leakage of important information about user data, the proposed scheme supports a client side deduplication of encrypted data, while simultaneously supporting public auditing of encrypted data. We used BLS signature based homomorphic linear authenticator to compute authentication tags for the PoW and integrity auditing. The proposed scheme satisfied the security objectives, and improved the problems of the existing schemes. In addition, it provides better efficiency than the existing schemes in the viewpoint of client-side computational overhead. Finally, we designed two variations for higher security and better performance. The first variance guarantees higher security in the sense that a legitimate user can be an adversary. The second variance provides better performance from the perspective of the clients, by permitting low-powered clients to perform upload procedure very efficiently by passing on their costly operations to the CSS.