Quorum systems are a key abstraction in distributed fault-tolerant computing for capturing trust assumptions. They can be found at the core of many algorithms for implementing reliable broadcasts, shared memory, consensus and other problems. This paper introduces asymmetric Byzantine quorum systems that model subjective trust. Every process is free to choose which combinations of other processes it trusts and which ones it considers faulty. Asymmetric quorum systems strictly generalize standard Byzantine quorum systems, which have only one global trust assumption for all processes. This work also presents protocols that implement abstractions of shared memory, broadcast primitives, and a consensus protocol among processes prone to Byzantine faults and asymmetric trust. The model and protocols pave the way for realizing more elaborate algorithms with asymmetric trust.

翻译：仲裁系统是分布式容错计算中用于捕获信任假设的关键抽象，存在于许多实现可靠广播、共享内存、共识及其他问题的算法核心。本文提出了一种模拟主观信任的非对称拜占庭仲裁系统。每个进程可自主选择信任的其他进程组合以及被其视为故障的进程。非对称仲裁系统严格推广了标准拜占庭仲裁系统——后者对所有进程仅有一个全局信任假设。本研究还提出了在拜占庭故障与异步信任环境下，实现共享内存抽象、广播原语及共识协议的方案。该模型与协议为实现更精细的异步信任算法奠定了基础。