Majority is not enough: Bitcoin mining is vulnerable

Ittay Eyal; Emin Gün Sirer

doi:https://doi.org/10.1007/978-3-662-45472-5_28

Majority is not enough: Bitcoin mining is vulnerable

Ittay Eyal, Emin Gün Sirer

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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 mining protocol is incentive-compatible and secure against colluding minority groups, that is, it incentivizes miners to follow the protocol as prescribed.

We show that the Bitcoin mining 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.

Unless certain assumptions are made, selfish mining may be feasible for any group size of colluding miners. We propose a practical modification to the Bitcoin protocol that protects Bitcoin in the general case. It prohibits selfish mining by 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.

Original language	English
Title of host publication	Financial Cryptography and Data Security - 18th International Conference, FC 2014, Revised Selected Papers
Editors	Reihaneh Safavi-Naini, Nicolas Christin
Pages	436-454
Number of pages	19
ISBN (Electronic)	9783662454718
DOIs	https://doi.org/10.1007/978-3-662-45472-5_28
State	Published - 2014
Externally published	Yes
Event	18th International Conference on Financial Cryptography and Data Security, FC 2014 - Christ Church, Barbados Duration: 3 Mar 2014 → 7 Mar 2014

Publication series

Name	Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume	8437

Conference

Conference	18th International Conference on Financial Cryptography and Data Security, FC 2014
Country/Territory	Barbados
City	Christ Church
Period	3/03/14 → 7/03/14

All Science Journal Classification (ASJC) codes

Theoretical Computer Science
General Computer Science

Access to Document

https://doi.org/10.1007/978-3-662-45472-5_28

Cite this

Eyal, I., & Sirer, E. G. (2014). Majority is not enough: Bitcoin mining is vulnerable. In R. Safavi-Naini, & N. Christin (Eds.), Financial Cryptography and Data Security - 18th International Conference, FC 2014, Revised Selected Papers (pp. 436-454). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 8437). https://doi.org/10.1007/978-3-662-45472-5_28

Eyal, Ittay ; Sirer, Emin Gün. / Majority is not enough : Bitcoin mining is vulnerable. Financial Cryptography and Data Security - 18th International Conference, FC 2014, Revised Selected Papers. editor / Reihaneh Safavi-Naini ; Nicolas Christin. 2014. pp. 436-454 (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)).

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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 mining protocol is incentive-compatible and secure against colluding minority groups, that is, it incentivizes miners to follow the protocol as prescribed.We show that the Bitcoin mining 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.Unless certain assumptions are made, selfish mining may be feasible for any group size of colluding miners. We propose a practical modification to the Bitcoin protocol that protects Bitcoin in the general case. It prohibits selfish mining by 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.",

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Eyal, I & Sirer, EG 2014, Majority is not enough: Bitcoin mining is vulnerable. in R Safavi-Naini & N Christin (eds), Financial Cryptography and Data Security - 18th International Conference, FC 2014, Revised Selected Papers. Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), vol. 8437, pp. 436-454, 18th International Conference on Financial Cryptography and Data Security, FC 2014, Christ Church, Barbados, 3/03/14. https://doi.org/10.1007/978-3-662-45472-5_28

Majority is not enough: Bitcoin mining is vulnerable. / Eyal, Ittay; Sirer, Emin Gün.
Financial Cryptography and Data Security - 18th International Conference, FC 2014, Revised Selected Papers. ed. / Reihaneh Safavi-Naini; Nicolas Christin. 2014. p. 436-454 (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 8437).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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Eyal I, Sirer EG. Majority is not enough: Bitcoin mining is vulnerable. In Safavi-Naini R, Christin N, editors, Financial Cryptography and Data Security - 18th International Conference, FC 2014, Revised Selected Papers. 2014. p. 436-454. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)). doi: https://doi.org/10.1007/978-3-662-45472-5_28

Majority is not enough: Bitcoin mining is vulnerable

Abstract

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All Science Journal Classification (ASJC) codes

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