Sharding-Based Asynchronous Coordination for Secure and Scalable Peer-to-Peer Energy Trading Under Delays and Attacks

The proliferation of distributed energy resources has enabled the emergence of prosumers and peer-to-peer (P2P) energy trading. However, many existing decentralized market clearing schemes that require iterative message exchanges are vulnerable to false data injection (FDI) and can stall under heterogeneous communication delays. Blockchain solutions enhance integrity but often rely on synchronous optimization and global consensus, yielding excessive overhead. In this paper, a sharding-based asynchronous coordination mechanism for network-constrained P2P energy trading is developed. First, an asynchronous decentralized optimization method is developed to clear the market with respect to network constraints. Second, a dynamic sharding method is proposed to partition prosumers into low-latency shards by jointly considering trading relationships and communication delays, thereby localizing coordination and reducing cross-network synchronization. Third, a lightweight consensus mechanism that integrates asynchronous updates with a chained verification structure is designed to verify message correctness and detect malicious behaviors, thereby enabling fast intrashard agreement without the need for global synchronous rounds. Case studies demonstrate that the proposed approach preserves scalability and reduces the overall runtime by 79.15% compared with benchmark mechanisms while maintaining secure clearing performance under attack scenarios.