Paper 2024/363

Selfish Mining Time-Averaged Analysis in Bitcoin: Is Orphan Reporting an Effective Countermeasure?

Roozbeh Sarenche, KU Leuven
Ren Zhang, Nervos
Svetla Nikova, KU Leuven
Bart Preneel, KU Leuven
Abstract

A Bitcoin miner who owns a sufficient amount of mining power can perform selfish mining to increase its relative revenue. Studies have demonstrated that the time-averaged profit of a selfish miner starts to rise once the mining difficulty level gets adjusted in favor of the attacker. Selfish mining profitability lies in the fact that orphan blocks are not incorporated into the current version of Bitcoin's difficulty adjustment mechanism (DAM). Therefore, it is believed that considering the count of orphan blocks in the DAM can result in complete unprofitability for selfish mining. In this paper, we disprove this belief by providing a formal analysis of the selfish mining time-averaged profit. We present a precise definition of the orphan blocks that can be incorporated into calculating the next epoch's target and then introduce two modified versions of DAM in which both main-chain blocks and orphan blocks are incorporated. We propose two versions of smart intermittent selfish mining, where the first one dominates the normal intermittent selfish mining, and the second one results in selfish mining profitability under the modified DAMs. Moreover, we present the orphan exclusion attack with the help of which the attacker can stop honest miners from reporting the orphan blocks. Using combinatorial tools, we analyze the profitability of selfish mining accompanied by the orphan exclusion attack under the modified DAMs. Our results show that even when considering orphan blocks in the DAM, selfish mining can still be profitable. However, the level of profitability under the modified DAMs is significantly lower than that observed under the current version of Bitcoin DAM, suggesting that orphan reporting can be considered an effective countermeasure for selfish mining in the presence of payoff-maximizing miners.

Metadata
Available format(s)
PDF
Category
Attacks and cryptanalysis
Publication info
Preprint.
Keywords
blockchainselfish miningdifficulty adjustment
Contact author(s)
roozbeh sarenche @ esat kuleuven be
ren @ nervos org
svetla nikova @ esat kuleuven be
bart preneel @ esat kuleuven be
History
2024-12-06: last of 2 revisions
2024-02-28: received
See all versions
Short URL
https://ia.cr/2024/363
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2024/363,
      author = {Roozbeh Sarenche and Ren Zhang and Svetla Nikova and Bart Preneel},
      title = {Selfish Mining Time-Averaged Analysis in Bitcoin: Is Orphan Reporting an Effective Countermeasure?},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/363},
      year = {2024},
      url = {https://eprint.iacr.org/2024/363}
}
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