Simple and Fast Signature-Free Blockchain Consensus

2026-09-26

AI Summary

This study addresses the prohibitive overhead of post-quantum signatures in blockchain consensus by proposing a generalized Simplex framework based on view-consistency abstraction, alongside two eventually synchronous signature-free consensus protocols. By introducing a novel view-consistency mechanism that unifies multiple protocol paradigms and incorporating O(n²) communication complexity optimizations, this work overcomes the performance bottlenecks inherent in traditional signature-dependent approaches. The proposed solution achieves optimal good-case commit latency and non-speculative two-latency block production, yielding three-latency confirmation under a fault-tolerance threshold of f < n/3 and reducing it to two latencies when f < n/5. Balancing rapid block confirmation with optimistic responsiveness, this project validates both the practical efficiency and theoretical significance of signature-free consensus.

Abstract

Signature-free protocols avoid the cost of post-quantum signatures. We present two simple signature-free blockchain consensus protocols for eventual synchrony with optimal good-case commit latency (three message delays for \(f<n/3\) and two for \(f<n/5\)), optimistic responsiveness, a block time of only two message delays without speculation, and \(O(n^2)\) communication per view. They instantiate Generic Simplex, a blockchain consensus construction parameterized by a new abstraction called view agreement. The same construction also captures Simplex, Minimmit, and a new synchronous signature-free protocol with optimal good-case commit latency of two message delays for \(f<n/4\).

Problem

• signature-free consensus
• blockchain
• post-quantum
• eventual synchrony
• commit latency

Innovation

• signature-free consensus
• blockchain
• eventual synchrony
• view agreement
• optimal commit latency