[Research] Bitcoin After Block Rewards : preventing miner's deviation when the Bitcoin rewards is zero

In the exploration of blockchain security vulnerabilities, particularly around double-spending attacks, the modeling of contests at various levels reveals significant insights into the dynamics between attackers and defenders. The current discourse extends from the premise that both attackers and defenders possess "dark capacity," which suggests an inherent symmetry in capabilities but not necessarily in outcomes. This symmetry raises the question of whether hidden capacities inherently favor attack strategies or defensive maneuvers, a determination that hinges on detailed modeling of these interactions.

The work by Budish (2024) Budish (QJE 2024) delves into the double-spend contest using a fixed acceptance rule without a reactive defender, leading to conclusions about the limits imposed by economic considerations under these assumptions. The absence of a strategic defender in this model and others, such as those presented by Bonneau in 2016 and 2018 Bonneau (FC'16) and Bonneau et al. (FC'18), where attack-capacity rental and acquisition are explored, similarly lack a counteractive defense strategy, leading to unopposed attack scenarios.

However, the research by Moroz et al. in 2020 Moroz, Aronoff, Narula & Parkes (2020) introduces a contrasting scenario where the potential for a victim to counter-fork introduces a form of deterrence, showcasing that when defensive moves are possible, they can prevent attacks altogether, indicating a collapse when removed and deterrence when restored. This pattern underscores the critical role of reactive defense capabilities in shaping the outcomes of such contests.

The implications of these studies are crucial for future research and modeling in blockchain security. They suggest that assumptions regarding the presence or absence of reactive defenders significantly influence the outcomes of theoretical models and should be explicitly acknowledged in research to accurately bound the claims made. As such, either the specific modeling of these contests needs to include various defensive strategies, or the limitations of models based on the no-reactive-defender assumption need to be clearly stated and cited to outline the scope and applicability of the findings. This approach ensures clarity and precision in understanding the dynamics at play in blockchain security challenges.