A decentralized document management system using blockchain and secret sharing

The use of digital documents is exploding around the world due to high productivity and convenience. However, the digital documents have some security issues. For example, when a user who has the permission behaves maliciously for his/her benefit, the digital document can be easily falsified. In this paper, we propose a decentralized document management system (DDMS) to improve security of a digital document. DDMS first distributes access permission to multiple users for higher security of the document. To do this, DDMS encrypts a document via a symmetric key and splits the key via a Shamir's secret sharing scheme. And, DDMS manages each split keys using blockchian and reconstructs the complete symmetric key when the document is retrieved via a devised smart contract. We implement DDMS based on Ethereum blockchain. The experimental results show that the proposed DDMS can provide higher security with a reasonable performance overhead compared with other three types of DMSs.