Blockchain-based Notarization System: A Decentralized Approach to Document Authentication using Smart Contracts and Public Key Infrastructure
Traditional notarization processes are labour-intensive, time-consuming, and susceptible to fraud and human error. The rapid proliferation of e-government services and digital transactions has created an urgent demand for automated, tamper-resistant document authentication mechanisms. This paper proposes and implements a fully automated Blockchain-Based Notarization System (BBNS) that leverages national electronic identity (eID) cards with Public Key Infrastructure (PKI), smart contracts deployed on the Ethereum blockchain, and cryptographic hashing to authenticate documents without requiring third-party intermediaries. The system performs digital signature verification within smart contracts, stores authenticated records immutably on-chain, and issues blockchain transaction receipts as legally verifiable certificates of notarization. A working prototype was developed and evaluated on 500 test transactions, demonstrating high accuracy, tamper-resistance, and practical viability for e-government deployment. The proposed system achieves an authentication accuracy of 97.4%, a precision of 98.1%, an F1-score of 97.7%, and an ROC AUC of 0.987— outperforming conventional digital notarization approaches across key performance metrics including verification speed, security, and transparency. These results establish the BBNS as a technically sound and practically deployable solution for decentralized public-sector notarization.