Biblio

With the vast increase in data transmission due to a large number of information collected by devices, data management, and security has been a challenge for organizations. Many data owners (DOs) outsource their data to cloud repositories due to several economic advantages cloud service providers present. However, DOs, after their data are outsourced, do not have complete control of the data, and therefore, external systems are incorporated to manage the data. Several kinds of research refer to the use of encryption techniques to prevent unauthorized access to data but prove to be deficient in providing suitable solutions to the problem. In this article, we propose a secure fine-grain access control system for outsourced data, which supports read and write operations to the data. We make use of an attribute-based encryption (ABE) scheme, which is regarded as a suitable scheme to achieve access control for security and privacy (confidentiality) of outsourced data. This article considers different categories of data users, and make provisions for distinct access roles and permissible actions on the outsourced data with dynamic and efficient policy updates to the corresponding ciphertext in cloud repositories. We adopt blockchain technologies to enhance traceability and visibility to enable control over outsourced data by a DO. The security analysis presented demonstrates that the security properties of the system are not compromised. Results based on extensive experiments illustrate the efficiency and scalability of our system.

Cloud computing is becoming more and more popular day by day due to its maintenance, multitenancy and performance. Data owners are motivated to outsource their data to the cloud servers for resource pooling and productivity where multiple users can work on the same data concurrently. These servers offer great convenience and reduced cost for the computation, storage and management of data. But concerns can persist for loss of control over certain sensitive information. The complexity of security is largely intensified when data is distributed over a greater number of devices and data is shared among unrelated users. So these sensitive data should be encrypted for solving these security issues that many consumers cannot afford to tackle. In this paper, we present a dynamic searchable encryption scheme whose update operation can be completed by cloud server while reserving the ability to support multi-keyword ranked search. We have designed a scheme where dynamic operations on data like insert, update and delete are performed by cloud server without decrypting the data. Thus this scheme not only ensures dynamic operations on data but also provides a secure technique by performing those tasks without decryption. The state-of-the-art methods let the data users retrieve the data, re-encrypt it under the new policy and then send it again to the cloud. But our proposed method saves this high computational overhead by reducing the burden of performing dynamic operation by the data owners. The secure and widely used TF × IDF model is used along with kNN algorithm for construction of the index and generation of the query. We have used a tree-based index structure, so our proposed scheme can achieve a sub-linear search time. We have conducted experiments on Amazon EC2 cloud server with three datasets by updating a file, appending a file and deleting a file from the document collection and compared our result with the state-of-the-art method. Results show th- t our scheme has an average running time of 42ms which is 75% less than the existing method.