A Secured Proxy-Based Data Sharing Module in IoT Environments Using Blockchain

Access and utilization of data are central to the cloud computing paradigm. With the advent of the Internet of Things (IoT), the tendency of data sharing on the cloud has seen enormous growth. With data sharing comes numerous security and privacy issues. In the process of ensuring data confidentiality and fine-grained access control to data in the cloud, several studies have proposed Attribute-Based Encryption (ABE) schemes, with Key Policy-ABE (KP-ABE) being the prominent one. Recent works have however suggested that the confidentiality of data is violated through collusion attacks between a revoked user and the cloud server. We present a secured and efficient Proxy Re-Encryption (PRE) scheme that incorporates an Inner-Product Encryption (IPE) scheme in which decryption of data is possible if the inner product of the private key, associated with a set of attributes specified by the data owner, and the associated ciphertext is equal to zero 0 . We utilize a blockchain network whose processing node acts as the proxy server and performs re-encryption on the data. In ensuring data confidentiality and preventing collusion attacks, the data are divided into two, with one part stored on the blockchain network and the other part stored on the cloud. Our approach also achieves fine-grained access control

Efficient Implementation of a Proxy-based Protocol for Data Sharing on the Cloud

In this paper, we provide a secure and efficient outsourcing scheme for multi-owner data sharing on the cloud. More in detail we consider the scenario where multiple data owners outsource their data to an untrusted cloud provider, and allow authorized users to query the resulting database, composed of the encrypted data contributed by the different owners. The scheme relies on a proxy re-encryption technique that is implemented using an El-Gamal Elliptic Curve (ECC) crypto-system. We experimentally assess the efficiency of the implementation in terms of computation time, including the key translation process, data encryption and re-encryption modules, and show that it improves over previous proposals