Blockchain-Based Document Verification System Using Ethereum Smart Contracts and Cryptographic Hashing

Abstract

In this paper, we presented an e-Registry prototype that builds on the decentralized and tamper-evident nature of Ethereum to authenticate digital documents. The system is a gas-efficient Smart Contract on the Ethereum blockchain that stores SHA-256 hashes of documents, so your sensitive files are secure with us, but we don't know what they are! Accessible through a web-based user interface using MetaMask for transaction signing and the Web Crypto API for client-side hashing of documents offers an intuitive privacy-preserving process. Finally, system diagnostics and security reports can be generated using Python-based tools and hashed to store on the blockchain for validation. Running on the Ethereum Sepolia testnet, the system provides practical efficiency, with transaction fees of 0.0005-0.001 SepoliaETH and verification delay less than 3 seconds. This provides an alternative to traditional centralized verification systems that suffer from single points of failure, lack of transparency, and reliance on third-party services by offering a secure and tamper-resistant decentralized proof of existence for digital files.