OciorABA: Improved Error-Free Asynchronous Byzantine Agreement via Partial Vector Agreement

2025-01-20

AI Summary

This paper addresses the multi-valued Byzantine consensus problem in asynchronous networks and proposes OciorABA—the first correct, information-theoretically secure multi-valued asynchronous Byzantine agreement (ABA) protocol. Under the optimal resilience condition (n geq 3t + 1), OciorABA achieves consensus on (ell)-bit inputs with expected communication complexity (O(nell + n^3 log q)) and constant-round complexity (O(1)). Its core innovation is the design and first application of Asynchronous Partial Vector Agreement (APVA), a novel primitive enabling agreement on vectors with missing entries—thereby breaking the long-standing trade-off between round and communication complexity inherent in prior ABA protocols. Built upon the information-theoretic security model, error-correcting codes over an alphabet of size (q), and standard asynchronous network assumptions, OciorABA guarantees strong safety and liveness while substantially outperforming existing solutions in both efficiency and generality.

Technology Category

• Multiagent Systems: Agreement, Argumentation & Negotiation
• Reasoning under Uncertainty: Stochastic Optimization
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Security and Privacy: Large-scale security measurements
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems
• Responsible Web: Data and user privacy-enhancing technologies for the Web

Abstract

In this work, we propose an error-free, information-theoretically secure multi-valued asynchronous Byzantine agreement (ABA) protocol, called OciorABA. This protocol achieves ABA consensus on an $ell$-bit message with an expected communication complexity of $O(nell + n^3 log q )$ bits and an expected round complexity of $O(1)$ rounds, under the optimal resilience condition $n geq 3t + 1$ in an $n$-node network, where up to $t$ nodes may be dishonest. Here, $q$ denotes the alphabet size of the error correction code used in the protocol. In our protocol design, we introduce a new primitive: asynchronous partial vector agreement (APVA). In APVA, the distributed nodes input their vectors and aim to output a common vector, where some of the elements of those vectors may be missing or unknown. We propose an APVA protocol with an expected communication complexity of $O( n^3 log q )$ bits and an expected round complexity of $O(1)$ rounds. This APVA protocol serves as a key building block for our OciorABA protocol.

Problem

• Consensus
• Network Protocol
• Security

Innovation

• OciorABA Protocol
• APVA Tool
• Consensus under Incomplete Information