A Secure Blockchain-Based Offline Payment System with Fraud Window Analysis

Abstract

The rapid growth of digital payment systems has increased the demand for secure and reliable payment mechanisms capable of operating in environments with intermittent or unavailable Internet connectivity. Conventional blockchain-based payment systems typically require continuous network access for transaction validation and settlement, which limits their applicability in rural areas, disaster-affected regions, and other low-connectivity environments. This research presents a Secure Blockchain-Based Offline Payment System with Explicit Fraud Window Analysis, which allows transactions to be created and stored locally during periods of network unavailability and synchronized with the Ethereum blockchain once connectivity is restored. The proposed system integrates an offline wallet, digitally signed transaction processing, local transaction verification, blockchain-based settlement, and a fraud-detection mechanism. Its central contribution is the explicit measurement of the fraud window, the time interval between offline transaction creation and blockchain synchronization, which is analysed alongside pending-transaction activity and trust-related parameters to estimate transaction risk. The system was implemented using Solidity, Ethereum, Hardhat, Ethers.js, JavaScript, Node.js, and MetaMask. The resulting prototype demonstrates the feasibility of secure offline transaction processing that preserves blockchain-based final settlement while providing measurable visibility into the security risk introduced by delayed synchronization.