Cryptology ePrint Archive: Report 2015/518

Broadcasting Intermediate Blocks as a Defense Mechanism Against Selfish-Mine in Bitcoin

Ren Zhang

Abstract: The selfish-mine strategy in Bitcoin allows a miner to gain mining rewards more than her fair share. Prior defenses focus on preventing the attacker from winning a block race of equal-length chains. However, an attacker with more than one third of the computational power can still earn more block rewards even if she loses all equal-length block races. In this work we propose a novel defense mechanism. Our defense requires miners to publish intermediate blocks, or in-blocks for short, blocks that are valid with slightly lower puzzle difficulty, and mine on each others' in-blocks. When a fork happens, the branch with most total amount of work, rather than the longest chain, will be adopted. Under our scheme, a selfish miner needs to have almost half of the computational power of the network to gain an unfair advantage, thus the selfish-mine strategy is no longer a threat to the system.

Category / Keywords: applications / Bitcoin selfish-mine

Date: received 29 May 2015

Contact author: ren zhang at esat kuleuven be

Available format(s): PDF | BibTeX Citation

Version: 20150530:070622 (All versions of this report)

Short URL: ia.cr/2015/518

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