Secure Encrypted Data Deduplication with Ownership Proof and User Revocation

Ciphertext policy attribute-based encryption (CP-ABE) is a promising cryptographic technology and a key component that enable secure data sharing in a cloud environment through fine-grained access control. Since it was introduced, many interesting schemes have been proposed. However, in addition to managing data sharing through access control, a comprehensive scheme should also cater for user revocation and ciphertext queries. This is because in a cloud environment new users may join while existing users may leave the system. At the same time, given the potentially large amount of data stored in a cloud storage, user should be able to retrieve the required files efficiently in a privacy-preserving manner. To address the above issue, in this paper, we propose a practical searchable CP-ABE scheme supporting user revocation. In contrast to existing schemes that provide only single keyword query, our efficient search function provides conjunctive search, which allows user to locate a ciphertext related to a set of keywords. The computation overhead of our user revocation is at least on par with existing schemes. Besides, the security analysis indicates that the proposed scheme is secure under the decisional Bilinear Diffie-Hellman assumption. We also provide extensive experimental results to confirm the efficiency and feasibility of our proposed construction.

In recent years, cloud storage technology has been widely used in many fields such as education, business, medical and more because of its convenience and low cost. With the widespread applications of cloud storage technology, data access control methods become more and more important in cloud-based network. The ciphertext policy attribute-based encryption (CP-ABE) scheme is very suitable for access control of data in cloud storage. However, in many practical scenarios, all attributes of a user cannot be managed by one authority, so many multi-authority CP-ABE schemes have emerged. Moreover, cloud servers are usually semi-trusted, which may leak user information. Aiming at the above problems, we propose a fine-grained access control scheme with versatility for cloud storage based on multi-authority CP-ABE, named vFAC. The proposed vFAC has the features of large universe, no key escrow problem, online/offline mechanism, hidden policy, verifiability and user revocation. Finally, we demonstrate vFAC is static security under the random oracle model. Through the comparison of several existing schemes in terms of features, computational overhead and storage cost, we can draw a conclusion that vFAC is more comprehensive and scalable.

Cloud computing has empowered the individual user by providing seemingly unlimited storage space and availability and accessibility of data anytime and anywhere. Cloud service providers are able to maximize data storage space by incorporating data deduplication into cloud storage. Although data deduplication removes data redundancy and data replication, it also introduces major data privacy and security issues for the user. In this paper, a new privacy-preserving framework that addresses this issue is proposed. Our framework uses an efficient deduplication algorithm to divide a given file into smaller units. These units are then encrypted by the user using the combination of a secure hash function and a block encryption algorithm. An index tree of hash values of these units is also generated and encrypted using an asymmetric search encryption scheme by the user. This index tree will enable the cloud service provider to search through the index and return the requested units. We will show that our proposed framework will allow cloud service and storage providers to employ data deduplication techniques without giving them access to either the users' plaintexts or the users' decryption keys.

Nowadays, more and more corporate and private users outsource their data to cloud service provider. It is provide lots of services to the users. Due to the large amount of data stored by multiple users on cloud one critical problem must be faced by users. In this large amount of data there are so many copies of repeated data. Data duplication is compress repeated data. We can use this technique To make data management scalable and mitigate the increased amount of data. In the proposed system, we are going to used two cloud server, public cloud server and private cloud server. Public cloud server store data (hash, encrypted data) and compare hash which is generated by private cloud. After comparison hash is stored in the data base by private cloud. This proposed system used to mitigate the problem of data duplication. Based on this we can improve storage utilization and efficiency of cloud storage.

Data redundancy consumes huge storage space while setting up or employing cloud and fog storage. The dynamic cloud nature primarily focuses on the static environments which must be revised. Data deduplication solutions help minimize and control this issue by eradicating duplicate data from cloud storage systems. Since it might improve storage economy and security, data deduplication (DD) over encrypted data is a crucial problem in computing and storage systems. In this research, a novel approach to building secure deduplication systems across cloud and fog environments is developed. It uses MCDD and convergent cryptographic algorithms. The two most significant objectives of such systems are the focus of the suggested approach. Data redundancy must be minimized, but it also needs to be secured using a robust encryption method, which needs to be devised. The suggested approach is ideally suited for tasks like a user uploading new data to cloud storage or the fog. The proposed method might eliminate data redundancy by detecting redundancy at the block level. The testing results indicate that the recommended methodology can surpass a few cutting-edge techniques regarding computing effectiveness and security levels. The file is encrypted twice, once with the modified cryptographic model for deduplication (MCDD) and once with convergence encryption (CE).

E-governance can be implemented very effectively using the cloud computing technologies. Security and privacy of data are the major challenges in cloud-based e-governance systems. With proper access control and user revocation schemes, we can protect the privacy and security of data stored in cloud servers used for e-governance. There are a lot of techniques to achieve the controlled access in cloud computing. In some applications of e-government, the users should be allowed to access data, only for a specific period of time. In this paper, we introduce a temporal access control scheme based on attribute-based encryption (ABE), which allows users to access the data according to their access policy and for a specific time period only. Our model includes both the temporal access scheme and a time-based proxy re-encryption scheme to allow a user's access right to expire automatically.

We propose a new and efficient scheme for broadcast encryption. A broadcast encryption system allows a broadcaster to send an encrypted message to a dynamically chosen subset RS, |RS|=n, of a given set of users, such that only users in this subset can decrypt the message. An important component of broadcast encryption schemes is revocation of users by the broadcaster, thereby updating the subset RS. Revocation may be either temporary, for a specific cipher text, or permanent. In the existing public key schemes which support temporary revocation of the users, the broadcaster is required to keep track of the revoked users. We present the first public key broadcast encryption scheme that supports permanent revocation of users. Unlike previous schemes, the broadcaster in our scheme should not keep track of the revoked users (saving memory and computation power). Our scheme is fully collusion-resistant. In other words, even if all the revoked users collude, the revoked user cannot encrypt messages without receiving new keys from the broadcaster. The procedure is based on Cipher-text Policy Attribute-Based Encryption (CP-ABE). The overhead of revocation in our system is constant in all major performance measures including length of private and public keys, computational complexity, user's storage space, and computational complexity of encryption and decryption. The scheme we construct improves on our original scheme in a poster presentation [7] by a factor of O(log n) in all major performance measures.

<span lang="EN-US">Cloud Computing is the ability to improve the utility or train new human resources without investing in new infrastructure, or add capabilities to existence without the latest software licensing. It expanded the capabilities of Information Technology (IT). From the past few years, cloud computing has developed from a good business concept in the best rising sectors of the IT industry. But more information on individuals and companies was put in the cloud, and concerns began to think about how secure the cloud environment was. Despite cloud surrounding structures, enterprise users still do not want to expand their business in the cloud. Security reduces the growth of cloud computing and continues to spread the market with complexity with data privacy and data protection. The security of cloud computing has constantly been an significant aspect of improved quality of service from cloud service providers. Data storage in the cloud has a problem related to data security. However, cloud computing construct many new security challenges which have not been well examine. In order to ensure that the user's data in the cloud is secure, we have proposed an effective mechanism with a distinctive feature of data integrity and privacy. This paper focusing on problems relating to the cloud data storage techniques and security in virtual environment. We recommend a method for providing data storage and security in cloud using public key Cryptosystem, which uses the concept of the modified RSA algorithm to provide better security for the data stored in the cloud. </span>

In today's digital era, the exponential growth of data necessitates effective storage and management solutions. The cloud has vast storage possibilities to store huge amounts of data. Public access to the cloud leads to duplicate copies of data stored in the storage. Maintaining a single copy of data in the cloud is most important for efficient data storage management. This paper introduces a groundbreaking strategy for improving the efficacy of cloud storage through innovative data deduplication techniques at the block levels. The block-level duplication verification efficiently identifies the duplicate data in the storage. It helps to protect the duplicate storage in the cloud data storage infrastructure. The block-level deduplication technique uses variable-length blocks based on the duplicate content of the block. Initially, A file is divided into a number of blocks with a size of 5kb. According to the proposed method, If any block is partially matched with a block already stored in the cloud, then that block is further divided into smaller blocks based on the matching percentage. The smaller blocks help to deduplicate the data more effectively. The work is implemented in a live cloud setting with a C# application hosted on MyASP.NET. The proposed methodology's effectiveness is validated against existing deduplication techniques. The results reveal a marked improvement in storage utilization and data management, affirming the potential of the approach to revolutionize cloud storage efficiency.

As data sharing has become one of the most popular services offered by cloud storage, designing public auditing mechanisms for integrity of shared data becomes more important. Two problems which arise in shared data auditing include preserving users identity and collusion resistant revocation of users. When data stored at the cloud is shared among a group of users, different users may modify and sign different data blocks which leaks signer identities to the public verifier. Also, when a user is revoked from the group, signatures generated by this user should be re-signed by the cloud server using re-signature keys. In addition, collusion of cloud server and the revoked user should leak no information about the private key of other users. In this paper, by employing a new proxy re-signature scheme, we propose a public shared data auditing mechanism that provides identity privacy and collusion resistant user revocation, simultaneously. The proposed protocol requires only lightweight computations at the user side for signing data blocks in real-time online phase. Moreover, our protocol supports large dynamic group of users, batch auditing and dynamic data operations. Experimental results demonstrate excellent efficiency of our scheme in comparison to the state of the art.

Deduplication is an important technology in the cloud storage service. For protecting user privacy, sensitive data usually have to be encrypted before outsourcing. This makes secure data deduplication a challenging task. Although convergent encryption is used to securely eliminate duplicate copies on the encrypted data, these secure deduplication techniques support only exact data deduplication. That is, there is no tolerance of differences in traditional deduplication schemes. This requirement is too strict for multimedia data including image. For images, typical modifications such as resizing and compression only change their binary presentation but maintain human visual perceptions, which should be eliminated as duplicate copies. Those perceptual similar images occupy a lot of storage space on the remote server and greatly affect the efficiency of deduplication system. In this paper, we first formalize and solve the problem of effective fuzzy image deduplication while maintaining user privacy. Our solution eliminates duplicated images based on the measurement of image similarity over encrypted data. The robustness evaluation is given and demonstrates that this fuzzy deduplication system is able to duplicate perceptual similar images, which optimizes the storage and bandwidth overhead greatly in cloud storage service.

Cloud storage systems save disk space and bandwidth through deduplication technology, but with the use of this technology has been targeted security attacks: the attacker can get the original file just use hash value to deceive the server to obtain the file ownership. In order to solve the above security problems and the different security requirements of cloud storage system files, an efficient information theory security proof of ownership scheme is proposed. This scheme protects the data through the convergence encryption method, and uses the improved block-level proof of ownership scheme, and can carry out block-level client deduplication to achieve efficient and secure cloud storage deduplication scheme.

Data deduplication is a valuable technique for compressing and minimizing data duplication during data transfers, especially in cloud environments. By eliminating redundant data, it optimizes transmission capacity and reduces memory usage. To ensure the integrity of sensitive data, encryption is applied throughout the deduplication process. The SHA algorithm is commonly used for storing text data during deduplication. It generates security bits by padding the text and computes a hash consisting of hexadecimal, string, and integer data. Hash-based deduplication involves hashing the entire file and treating the hash values of text data as unique identifiers. This allows clients to identify duplicate data within the cloud. The Proof-of-Work (PoW) algorithm is widely utilized in blockchain networks like Bitcoin and Ethereum. Its primary function is to verify transactions through a process called mining. Miners engage in competition to solve complex mathematical problems, and the first one to find a solution is granted the right to add a new block to the blockchain. PoW relies on cryptographic hashing, such as the SHA-256 hashing function, to validate and secure transactions. On the other hand, the Proof of Retrievability (PoR) algorithm finds application in cloud computing systems. It serves as a consensus mechanism, ensuring that cloud storage providers store and retrieve data accurately. PoR enables cloud providers to demonstrate to consumers that their files can be fully recovered. This algorithm incorporates cryptographic proofs that validate the integrity and availability of the stored data. In cloud storage, deduplication is often implemented using the Memory mapping technique (MPT). This allows multiple data owners to store the same data in a single copy, enhancing storage efficiency. To maintain data security, encryption is applied both before and during the deduplication process, ensuring that sensitive information remains protected. In summary, data deduplication is a powerful method for compressing data, minimizing duplication, and optimizing transmission capacity. With encryption techniques and hash-based identification, it provides secure and efficient deduplication in cloud environments, while memory deduplication and MPT support further enhance performance and storage efficiency.

SummaryThe exponential growth of data poses a critical challenge for cloud storage systems. Redundant data consumes valuable storage space and increases infrastructure costs. Data deduplication, a technique for eliminating duplicate data copies, offers a promising solution. However, existing deduplication techniques often compromise data security, especially when dealing with encrypted data. This paper proposes a novel approach that merges convergent encryption (CE) with data deduplication. CE leverages user data itself to generate unique encryption keys, enabling secure deduplication on encrypted data. We analyze existing literature on secure data deduplication and categorize various techniques using UML activity diagrams. We then present our proposed CE‐based deduplication system, outlining its functionalities through UML diagrams. This research contributes to the field of secure data storage by proposing a novel and secure deduplication approach. By demonstrating its efficiency and security benefits, this work paves the way for more efficient and secure cloud storage solutions. Finally, we demonstrate the system's effectiveness through a comparative analysis, highlighting its potential to significantly improve storage efficiency while maintaining data security.

An efficient fine-grained data access control system with a bounded service number