Blockchain-based decentralized storage networks: A survey

Blockchain is a new approach to create a distributed network which was first introduced in 2008. By the help of this disruptive technology a peer-to-peer network can be formed where nodes have to reach a consensus and form a chain from accepted blocks, while no central party or trusted controller is required. Among all the existing uses of this technology, decentralized storage systems are one of its prominent applications. Decentralized storage networks, are consisted of a group of people willing to rent out their unused hardware storage space. By implementing end-to-end encryption clients can securely transmit their files through a fully decentralized network and eliminate the risk of data failures that arise from centralized controls. In this network, storage providers are required to prove that they store unaltered files during the time. Also a smart contract between two parties is set out in which rental duration and cost that the customer needs to pay for using that storage space is clarified. This paper presents a comprehensive survey on the blockchain-based storage systems and how they work and then compares them with cloud-based storage networks. Also different techniques of consensus protocols in each group are explored. Next, we have an overview on the advantages and also weak points of blockchain-based storage systems. Finally, we discuss about future research directions.