Reputation-Based Leader Election under Partial Synchrony: Towards a Protocol-Independent Abstraction with Enhanced Guarantees

2025-12-13

AI Summary

Existing leader election frameworks for partially synchronous Byzantine Fault Tolerant (BFT) protocols suffer from tight protocol coupling, narrow applicability, and unbounded recovery time. Method: We propose the first protocol-agnostic leader election abstraction, formally specifying generic correctness and strong liveness guarantees. We design Sliding-Window Leader Election (SWLE), a reputation-driven mechanism that dynamically updates node reputation based on consensus behavior and amplifies Byzantine costs. Contribution/Results: We provide the first rigorous proof in the partial synchrony model establishing bounded recovery time and strong liveness. Evaluation across a 16-node, 4-region deployment shows a 4.2× throughput improvement, 75% reduction in end-to-end latency, 27% fewer malicious leaders, and baseline performance retention under fault-free conditions.

Technology Category

• Multiagent Systems: Mechanism Design
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• Security and Privacy: Data transparency and provenance
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Abstract

Leader election serves a well-defined role in leader-based Byzantine Fault Tolerant (BFT) protocols. Existing reputation-based leader election frameworks for partially synchronous BFTs suffer from either protocol-specific proofs, narrow applicability, or unbounded recovery after network stabilization, leaving an open problem. This paper presents a novel protocol-independent abstraction formalizing generic correctness properties and effectiveness guarantees for leader election under partial synchrony, enabling protocol-independent analysis and design. Building on this, we design the Sliding Window Leader Election (SWLE) mechanism. SWLE dynamically adjusts leader nominations via consensus-behavior-based reputation scores, enforcing Byzantine-cost amplification. We demonstrate SWLE introduces minimal extra overhead to the base protocol and prove it satisfies all abstraction properties and provides superior effectiveness. We show, with a 16-server deployment across 4 different regions in northern China, SWLE achieves up to 4.2x higher throughput, 75% lower latency and 27% Byzantine leader frequency compared to the state-of-the-art solution under common Byzantine faults, while maintaining efficiency in fault-free scenarios.

Problem

• Designs a protocol-independent abstraction for leader election under partial synchrony
• Creates a reputation-based mechanism with Byzantine-cost amplification enforcement
• Improves throughput and reduces latency compared to existing solutions

Innovation

• Protocol-independent abstraction formalizing leader election correctness properties
• Sliding Window Leader Election mechanism using behavior-based reputation scores
• Dynamic leader nomination with Byzantine-cost amplification for enhanced performance