Leader-based consensus algorithms are vulnerable to liveness and performance downgrade attacks. We explore the possibility of replacing leader election in Multi-Paxos with random exponential backoff (REB), a simpler approach that requires minimum modifications to the two phase Synod Paxos and achieves better resiliency under attacks. We propose Baxos, a new resilient consensus protocol that leverages a random exponential backoff scheme as a replacement for leader election in consensus algorithms. Our backoff scheme addresses the common challenges of random exponential backoff such as scalability and robustness to changing wide area latency. We extensively evaluate Baxos to illustrate its performance and robustness against two liveness and performance downgrade attacks using an implementation running on Amazon EC2 in a wide area network and a combination of a micro benchmark and YCSB-A workload on Redis. Our results show that Baxos offers more robustness to liveness and performance downgrade attacks than leader-based consensus protocols. Baxos outperforms Multi-Paxos and Raft up to 128% in throughput under liveness and performance downgrade attacks under worst case contention scenarios where each replica proposes requests concurrently.

翻译：基于领导者的共识算法易受活性与性能降级攻击的影响。本文探讨了在Multi-Paxos中用随机指数退避机制替代领导者选举的可能性。该方法仅需对两阶段Synod Paxos进行最小修改，即可在攻击下实现更强的容错能力。我们提出Baxos——一种新型鲁棒共识协议，该协议利用随机指数退避方案替代共识算法中的领导者选举机制。我们的退避方案解决了随机指数退避机制在可扩展性和广域延迟变化鲁棒性方面的常见挑战。通过在亚马逊EC2广域网络上部署的实施方案，结合Redis微基准测试与YCSB-A工作负载，我们对Baxos进行了全面评估，以验证其性能及对抗两种活性与性能降级攻击的鲁棒性。实验结果表明，相较于基于领导者的共识协议，Baxos对活性与性能降级攻击具有更强的鲁棒性。在最坏竞争场景（所有副本并发提交请求）下，Baxos在遭受活性与性能降级攻击时的吞吐量较Multi-Paxos和Raft最高提升128%。