Majority Is Not Enough: Bitcoin Mining Is Vulnerable
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abstract = {The Bitcoin cryptocurrency records its transactions in a public log called the blockchain. Its security rests critically on the distributed protocol that maintains the blockchain, run by participants called miners. Conventional wisdom asserts that the protocol is incentive-compatible and secure against colluding minority groups, i.e., it incentivizes miners to follow the protocol as prescribed. We show that the Bitcoin protocol is not incentive-compatible. We present an attack with which colluding miners obtain a revenue larger than their fair share. This attack can have significant consequences for Bitcoin: Rational miners will prefer to join the selfish miners, and the colluding group will increase in size until it becomes a majority. At this point, the Bitcoin system ceases to be a decentralized currency. Selfish mining is feasible for any group size of colluding miners. We propose a practical modification to the Bitcoin protocol that protects against selfish mining pools that command less than 1/4 of the resources. This threshold is lower than the wrongly assumed 1/2 bound, but better than the current reality where a group of any size can compromise the system.},
apice = {MajorityFc2014},
arxiv = {1311.0243},
author = {Ittay Eyal and Emin Gün Sirer},
booktitle = {Financial Cryptography and Data Security (FC 2014)},
doi = {10.1007/978-3-662-45472-5_28},
editor = {Nicolas Christin and Reihaneh Safavi-Naini},
eisbn = {978-3-662-45472-5},
eissn = {1611-3349},
isbn = {978-3-662-45471-8},
issn = {0302-9743},
journal = {Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)},
numpages = 19,
openalex = {W2886706106},
pages = {436--454},
publisher = {Springer},
series = {Lecture Notes in Computer Science},
title = {Majority Is Not Enough: Bitcoin Mining Is Vulnerable},
url = {https://link.springer.com/10.1007/978-3-662-45472-5_28},
urlpdf = {https://link.springer.com/content/pdf/10.1007/978-3-662-45472-5_28.pdf},
volume = 8437,
year = 2014
}