Cryptology ePrint Archive: Report 2018/239

RepuCoin: Your Reputation is Your Power

Jiangshan Yu and David Kozhaya and Jeremie Decouchant and Paulo Esteves-Verissimo

Abstract: Existing proof-of-work cryptocurrencies cannot tolerate attackers controlling more than 50% of the network’s computing power at any time, but assume that such a condition happening is “unlikely”. However, recent attack sophistication, e.g., where attackers can rent mining capacity to obtain a majority of computing power temporarily, render this assumption unrealistic. This paper proposes RepuCoin, the first system to provide guarantees even when more than 50% of the system’s computing power is temporarily dominated by an attacker. RepuCoin physically limits the rate of voting power growth of the entire system. In particular, RepuCoin defines a miner’s power by its ‘reputation’, as a function of its work integrated over the time of the entire blockchain, rather than through instantaneous computing power, which can be obtained relatively quickly and/or temporarily. As an example, after a single year of operation, RepuCoin can tolerate attacks compromising 51% of the network’s computing resources, even if such power stays maliciously seized for almost a whole year. Moreover, RepuCoin provides better resilience to known attacks, compared to existing proof-of-work systems, while achieving a high throughput of 10000 transactions per second (TPS).

Category / Keywords: Blockchain, Cryptocurrency, Fault tolerance, consensus.

Original Publication (with minor differences): IEEE Transactions on Computers

Date: received 2 Mar 2018, last revised 3 Feb 2019

Contact author: j yu research at gmail com

Available format(s): PDF | BibTeX Citation

Version: 20190203:182350 (All versions of this report)

Short URL: ia.cr/2018/239