Atomic Read/Write Memory in Signature-free Byzantine Asynchronous Message-passing Systems

TL;DR

This paper introduces a simple, signature-free algorithm for implementing atomic read/write memory in asynchronous message-passing systems with Byzantine failures, achieving optimal resilience with efficient message complexity.

Contribution

It presents a novel, cryptography-free algorithm for atomic memory in Byzantine systems, closely aligned with classical crash-failure algorithms but adapted for Byzantine resilience.

Findings

Achieves atomic memory with up to t<n/3 Byzantine failures

Uses no cryptography, simplifying implementation

Optimal resilience and message complexity for read/write operations

Abstract

This article presents a signature-free distributed algorithm which builds an atomic read/write shared memory on top of an $n$-process asynchronous message-passing system in which up to $t<n/3$ processes may commit Byzantine failures. From a conceptual point of view, this algorithm is designed to be as close as possible to the algorithm proposed by Attiya, Bar-Noy and Dolev (JACM 1995), which builds an atomic register in an $n$-process asynchronous message-passing system where up to $t<n/2$ processes may crash. The proposed algorithm is particularly simple. It does not use cryptography to cope with Byzantine processes, and is optimal from a $t$-resilience point of view ($t<n/3$). A read operation requires $O(n)$ messages, and a write operation requires $O(n^2)$ messages.