Chitin: A Security-Enhanced Proof-of-Stake Protocol With View-Interference Resilience

The Proof-of-Stake (PoS) protocol is emerging as one of the most promising blockchain consensus mechanisms, and Ethereum is also undergoing a significant transition to PoS, specifically by adopting Gasper. However, a particularly critical threat faced by existing view-dependent PoS, such as Gasper, lies in view-interference attacks, exemplified by balance attack and reorg attack. These attacks enable adversaries to prevent honest proposals from being committed, thereby directly compromising the fundamental liveness property of blockchain. Currently, there is no effective solution to mitigate such view-interference attacks. In this paper, we present Chitin, a novel view-dependent PoS protocol that is designed to enhance security and effectively mitigate all varieties of view-interference attacks. The core design of Chitin comprises a common set protocol that leverages an innovative deletion mechanism to achieve both a consistent message set and strong termination, while requiring only minimal support from Trusted Execution Environment through its basic validation module. Furthermore, we prove that Chitin not only satisfies safety and liveness, but also possesses resilience against view-interference attacks. Finally, we implement Chitin and conduct comparisons with existing works. The experimental results show that our protocol exhibits superior efficiency, resulting in significant improvements in throughput ranging from 33%-50%, along with reduced communication costs.