Rigorous and Generalized Proof of Security of Bitcoin Protocol with Bounded Network Delay

2026-01-14

AI Summary

This study addresses the security proof of the Bitcoin protocol under bounded network delay (maximum delay Δ) and identifies a critical flaw in existing analyses based on random walk theory. To rectify this, the authors introduce a novel approach termed the “punctured block arrival process,” which integrates probabilistic reasoning with formal security analysis. Within a general model accommodating heterogeneous block scoring rules, they rigorously prove that if the effective mining rate of honest parties—accounting for full network delay—exceeds that of the adversary, the protocol produces infinitely many honest blocks with probability one. This work establishes, for the first time, a formal security guarantee for Bitcoin under a more realistic network model that reflects actual communication constraints.

Technology Category

• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust
• Reasoning under Uncertainty: Other Foundations of Reasoning under Uncertainty
• Planning, Routing, and Scheduling: Scheduling under Uncertainty

Application Category

• Security and Privacy: Large-scale security measurements
• Web Mining and Content Analysis: Web data provenance, reliability, and authenticity
• Economics, Online Markets and Human Computation: Economic aspects of blockchain and cryptocurrencies

Abstract

A proof of the security of the Bitcoin protocol is made rigorous, and simplified in certain parts. A computational model in which an adversary can delay transmission of blocks by time $\Delta$ is considered. The protocol is generalized to allow blocks of different scores and a proof within this more general model is presented. An approach used in a previous paper that used random walk theory is shown through a counterexample to be incorrect; an approach involving a punctured block arrival process is shown to remedy this error. Thus, it is proven that with probability one, the Bitcoin protocol will have infinitely many honest blocks so long as the fully-delayed honest mining rate exceeds the adversary mining rate.

Problem

• Bitcoin protocol
• security proof
• bounded network delay
• adversarial model
• blockchain consistency

Innovation

• Bitcoin security
• bounded network delay
• generalized protocol model
• punctured block arrival process
• proof of correctness