We analyze how secure a block is after the block becomes k-deep, i.e., security-latency, for Nakamoto consensus under an exponential network delay model. We give parameter regimes for which transactions are safe when sufficiently deep in the chain. We compare our results for Nakamoto consensus under bounded network delay models and obtain analogous bounds for safety violation threshold. Next, modeling the blockchain system as a batch service queue with exponential network delay, we connect the security-latency analysis to sustainable transaction rate of the queue system. As our model assumes exponential network delay, batch service queue models give a meaningful trade-off between transaction capacity, security and latency. As adversary can attack the queue service to hamper the service process, we consider two different attacks for adversary. In an extreme scenario, we modify the selfish-mining attack for this purpose and consider its effect on the sustainable transaction rate of the queue.

翻译：我们在指数网络延迟模型下，分析了纳什共识中区块在达到k层深度后的安全性，即安全-延迟特性。我们给出了交易在链中足够深时安全的参数区间。将我们的结果与有界网络延迟模型下的纳什共识进行对比，获得了安全违规阈值的类似界限。接着，我们将区块链系统建模为具有指数网络延迟的批量服务队列，并将安全-延迟分析与队列系统的可持续交易率相关联。由于模型假设指数网络延迟，批量服务队列模型为交易容量、安全性与延迟之间的权衡提供了有意义的分析框架。考虑到攻击者可能通过攻击队列服务来干扰服务进程，我们针对攻击者设计了两种不同攻击方式。在极端场景下，我们修改了自私挖矿攻击以适配该场景，并探讨了其对队列可持续交易率的影响。