Sharded Consensus With Non-Sharded Security Bound

Blockchain sharding enhances transaction throughput for vote-based blockchains while preserving system decentralization. Existing sharded blockchains can only maintain reasonable performance by tolerating a smaller magnitude of adversarial nodes compared to the upper-bound adversarial population of non-sharded ones. They lack adequate distinction of adversarial behaviors, with safety attacks posing catastrophic consequences and liveness attacks being more manageable. This paper presents WaveSpreader, a novel blockchain sharding protocol in a synchronous communication network that tolerates the same upper-bound adversarial population as non-sharded blockchains. It achieves a notable transaction throughput with the help of a robust mitigation method that effectively mitigates the liveness attacks. Our study provides a comprehensive security analysis and experimental results confirming the efficacy of WaveSpreader.