On profitability of selfish mining

Understand

We review the so called selfish mining strategy in the Bitcoin network and compare its profitability to honest mining.We build a rigorous profitability model for repetition games.

• The time analysis of the attack has been ignored in the previous literature based on a Markov model,but is critical.
• Using martingale's techniques and Doob Stopping Time Theorem we compute the expected duration of attack cycles.
• We discover a remarkable property of the bitcoin network: no strategy is more profitable than the honest strategy before a difficulty adjustment.