  Stubborn mining attack greatly downgrades Bitcoin throughput and also
benefits malicious miners (attackers). This paper aims to quantify the impact
of block receiving delay on stubborn mining attack severity in imperfect
Bitcoin networks. We develop an analytic model and derive formulas of both
relative revenue and system throughput, which are applied to study attack
severity. Experiment results validate our analysis method and show that
imperfect networks favor attackers. The quantitative analysis offers useful
insight into stubborn mining attack and then helps the development of
countermeasures.
