DeCStor: A Framework for Privately and Securely Sharing Files Using a Public Blockchain

Abstract

Cloud services have become increasingly popular during the past few years. Through these services, users can store their data remotely and access them any time and from anywhere. These services are offered by centralized systems where an organization or company usually offers their resources to users. The centralized nature of these systems causes several problems; a single point of failure exists, security issues might provide unwarranted access to intruders and there are privacy issues to consider as well. A solution to these problems is the decentralization of the system. A core technology that can help in this respect is the blockchain. It does not require any centralized control and its security model is based on the nodes of the blockchain network to share and verify transactions. This work aims to develop a secure decentralized cloud service, which does not expose the users’ personal data. To this effect, a framework that implements a cloud service using the Ethereum blockchain ecosystem and the Swarm decentralized storage platform was developed. In this, file access is provided through user-specific decryption keys. By developing a decentralized cloud, using a secure encryption model for the data, a service which is more secure, and where the users have full control over their data is possible.