Security analyses for consensus protocols in blockchain research have primarily focused on the synchronous model, where point-to-point communication delays are upper bounded by a known finite constant. These models are unrealistic in noisy settings, where messages may be lost (i.e. incur infinite delay). In this work, we study the impact of message losses on the security of the proof-of-work longest-chain protocol. We introduce a new communication model to capture the impact of message loss called the $0-\infty$ model, and derive a region of tolerable adversarial power under which the consensus protocol is secure. The guarantees are derived as a simple bound for the probability that a transaction violates desired security properties. Specifically, we show that this violation probability decays almost exponentially in the security parameter. Our approach involves constructing combinatorial objects from blocktrees, and identifying random variables associated with them that are amenable to analysis. This approach improves existing bounds and extends the known regime for tolerable adversarial threshold in settings where messages may be lost.
翻译:块链研究中协商一致协议的安全分析主要侧重于同步模式, 即点到点通信延迟被已知的有限常数封住。 这些模式在噪音环境中是不切实际的, 电文可能会丢失( 造成无限延迟 ) 。 在这项工作中, 我们研究电文丢失对工作证明最长链协议安全的影响。 我们引入了一个新的通信模式, 以捕捉电文损失的影响, 称为 $- infty$ 模式, 并产生一个可容忍的对抗力量区域, 从而保证协商一致协议的安全。 这些担保是作为交易侵犯预期安全特性的可能性的简单约束。 具体地说, 我们证明这种违反概率在安全参数中几乎会急剧衰减。 我们的方法是从块树中绘制组合对象, 并找出可以分析的与它们相关的随机变量。 这种方法改进了现有的界限, 并扩展了在可能丢失电文的环境下可容忍的对抗阈值的已知制度 。