CT-ISG Scalable Byzantine Replication under Attack

随着网络环境变得越来越恶劣，即使是保护得很好的分布式信息系统，在构建时考虑到安全性，也可能会受到威胁。因此，构建能够正常运行并在部分系统受损时仍能提供足够性能的大规模分布式系统是最重要的挑战之一。拜占庭复制正在成为缓解服务器危害的一个有前途的方向。拜占庭复制协议的经验表明，潜在的理论基础存在相当大的缺陷。也就是说，用于推理和构建拜占庭复制算法的现有故障模型、度量和正确性标准不能捕获在广域环境中显现的属性。由于所有现有的拜占庭复制算法都是为满足标准的安全性和活跃性标准而设计的，因此它们都显示出标准模型没有涵盖的关键漏洞。该项目将为可扩展的广域拜占庭复制系统开发理论基础、体系结构框架和算法技术，从而在攻击下提供强大的性能保证。这包括：(1)扩展现有的理论故障模型，以更好地封装与可扩展广域拜占庭复制系统相关的独特特征和性能漏洞；(2)定义用于评估和比较不同体系结构、配置和算法的有用度量，重点关注它们在复杂攻击下的性能；(3)开发可扩展拜占庭复制体系结构框架，该框架可以根据特定广域系统的拓扑、性能和弹性要求进行定制；以及(4)为广域环境开发特定的算法，以在攻击下提供强大的性能保证。

As network environments become increasingly hostile, even well protected distributed information systems, constructed with security in mind, are likely to be compromised. Hence, architecting large-scale distributed systems that function correctly and provide adequate performance even when parts of them are compromised is one of the most important challenges. Byzantine replication is emerging as a promising direction to mitigate server compromise. Experience with Byzantine replication protocols reveals considerable shortcomings in the underlying theoretical foundation. Namely, existing fault models, metrics, and correctness criteria used to reason about and construct Byzantine replication algorithms, fail to capture properties that manifest themselves in wide-area environments. Since all existing Byzantine replication algorithms were designed to meet the standard safety and liveness criteria, they all exhibit critical vulnerabilities not covered by the standard models. This project will develop the theoretical foundation, architectural framework, and algorithmic techniques for a scalable wide-area Byzantine replication system that provides strong performance guarantees under attack. This includes: (1) expanding the existing theoretical fault models to better encapsulate the unique characteristics and performance vulnerabilities associated with scalable wide-area Byzantine replication systems; (2) defining useful metrics for evaluating and comparing different architectures, configurations, and algorithms with a focus on their performance under sophisticated attacks; (3) developing an architectural framework for scalable Byzantine replication that can be customized to topology, performance, and resiliency requirements of specific wide-area systems; and (4) developing specific algorithms for wide-area environments that provide strong performance guarantees under attack.