Exchanging Digital Documents Using Blockchain Technology

Physical documents have many challenges, due to being difficult to exchange and the potential of being lost and sabotaged. Digital documents seem to address some of these challenges, but because of the use of the Internet and reliance on third parties to share and preserve such documents, the privacy and integrity of the digital documents became difficult to maintain. The blockchain technology that Satoshi Nakamoto has proposed for financial transactions can be used to solve the problems of trust in centralized systems and the subversion and alteration thatthese transactions may be exposed to. Blockchain-based systems have shown their effectiveness and ability to solve most security problems related to exchanging systems' transactions. Hence,A decentralized system for exchanging digital documents, using Ethereum blockchain and InterPlanetary File System (IPFS), has been proposed to overcome the problems of using trusted third-parties in exchanging digital documents. The proposed system provides immutable and irreversible logs of the process of sending and receiving documents. In this framework, all registered users can encrypt the documents using the Advanced Encryption Standard (AES) Algorithm, send, and receive documents using the Ethereum Blockchain's smart contract. The framework was simulated locally using Ganache Blockchain and tested on the official Ethereum test network Ropsten, and the experimental results showed the feasibility of the proposed scheme. The smart contract used in the Ethereum blockchain was written in the Solidity programming language, and the website that was needed to interact with the blockchain was built using React and other different javascript libraries like web3. Additionally, Metamask wallet was used to create the Ethereum accounts which are required to connect and communicate with the Smart Contract that is implemented in the Ethereum blockchain. Finally, the model's results indicated that the model may cost an average of 0.0552$ per transaction, and this shows that the system is affordable. Also, the model has satisfied the three main security requirements which are confidentiality, integrity, and availability by using the suitable countermeasure for each one of them.