Selfish Mining Attacks Exacerbated by Elastic Hash Supply
This addresses security vulnerabilities in blockchain systems for users and miners, but it is incremental as it builds on prior selfish mining research by considering hash supply elasticity.
The paper tackles the problem of selfish mining attacks in Proof-of-Work blockchains by showing that these attacks can trigger a feedback loop where honest miners leave due to reduced profitability, potentially leading to chain collapse. The result includes empirical evidence of a correlation between profitability and hash rate, and theoretical analysis predicting collapse or stable equilibrium based on attacker share.
Several attacks have been proposed against Proof-of-Work blockchains, which may increase the attacker's share of mining rewards (e.g., selfish mining, block withholding). A further impact of such attacks, which has not been considered in prior work, is that decreasing the profitability of mining for honest nodes incentivizes them to stop mining or to leave the attacked chain for a more profitable one. The departure of honest nodes exacerbates the attack and may further decrease profitability and incentivize more honest nodes to leave. In this paper, we first present an empirical analysis showing that there is a statistically significant correlation between the profitability of mining and the total hash rate, confirming that miners indeed respond to changing profitability. Second, we present a theoretical analysis showing that selfish mining under such elastic hash supply leads either to the collapse of a chain, i.e., all honest nodes leaving, or to a stable equilibrium depending on the attacker's initial share.