A Secure and Flexible Blockchain-Based Offline Payment Protocol

Off-chain transactions aim to tackle the scalability issues of on- chain processes and enable smoother blockchain-based payments over unreliable networks. However, existing solutions often struggle to strike a balance between security and flexibility. Our hypothesis suggests that by leveraging loosely synchronized clocks and channels with known latency bounds, two offline parties can conduct secure and flexible off-chain transactions. To support this hypothesis, we’ve introduced a new blockchain-based offline payment protocol. Our approach utilizes on-chain smart contracts and offline wallet interactions to ensure resilience against intermittent on-chain connectivity. By employing platform-agnostic Trusted Execution Environments (TEEs) and open transactions, our protocol achieves flexible and trusted computations. Through empirical evaluation, conducted using Intel Software Guard Extensions (SGX), we have demonstrated that our protocol is highly efficient and offers advanced security and flexibility. Additionally, we’ve tested our construction against various real-world attacks, confirming its security and robustness within a universally composable framework under synchronous settings. This research significantly contributes to the development of safe and user- friendly offline payment solutions for blockchain technology