Year: 2024
Type: article
Abstract: Byzantine fault-tolerant causal ordering of messages is useful to many applications. Causal ordering requires a property that we term strong safety, and liveness. In this paper, we use execution histories to prove that it is impossible to solve causal ordering – strong safety and liveness – in a deterministic manner for unicasts, multicasts, and broadcasts in an asynchronous system with one or more Byzantine processes. We also define a weaker version of strong safety termed weak safety. We prove that it is impossible to solve causal ordering – weak safety and liveness – in a deterministic manner for unicasts and multicasts, in an asynchronous system with one or more Byzantine processes. In view of these impossibility results, we propose the Sender-Inhibition algorithm and the Channel Sync algorithm to provide causal order – weak safety and liveness – of unicasts under the Byzantine failure model in synchronous systems, which have a known upper bound on message latency. The algorithms operate under the synchronous system model, but are inherently asynchronous and offer a high degree of concurrency as lock-step communication is not assumed. The two algorithms provide different trade-offs. We also indicate how the algorithms can be extended to multicasts.
Authors: Anshuman Misra, Ajay D. Kshemkalyani
Institution: University of Illinois Chicago
Language: English
Subfield: Computer Networks and Communications
Field: Computer Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,495
OpenAlex ID: W4391992401