SHARE: Optimizing Secure Hub Allocation and Routing Efficiency in Payment Channel Networks

Payment channel hub (PCH), by leveraging a powerful hub to reliably provide off-chain payment services, offers an effective enhancement to payment channel networks (PCNs). However, existing approaches typically rely on a single hub to relay transactions and provide relationship anonymity between participants. This design lacks flexibility under high-frequency transaction scenarios and fail to adequately balance the security of off-chain payments with PCH efficiency. Moreover, current PCNs often adopt source routing, where each transaction path is predetermined without considering the dynamic distribution of large-scale payment requests, leading to load imbalance and even transaction deadlocks. To address these issues, we propose SHARE, a multi-PCH distributed routing scheme based on trusted execution environments (TEE), designed to optimize secure hub allocation and routing efficiency in PCNs. For the multi-hub allocation problem, SHARE balances the management and synchronization costs among participants, and employs mixed-integer linear programming along with supermodular optimization techniques to transform the NP-hard problem into a solvable form, enabling optimal or approximate solutions across various PCN scales. At the routing layer, SHARE integrates global network state with local sender requests to design a TEE-assisted, privacy-preserving distributed routing protocol that dynamically adjusts multipath flow rates, achieving high-throughput and deadlock-free transaction forwarding. We formally prove the security of the SHARE protocol under the universally composable framework. Experimental results demonstrate that SHARE achieves a 43.6% improvement in transaction success ratio and an over 181.5% enhancement in system throughput compared to state-of-the-art PCN solutions, effectively realizing a secure extension of PCNs.