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 (PoW) 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 (flash attacks), 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 defines a miner's power by its reputation as a function integrated over the entire blockchain, rather than through its sheer computing power which can be obtained relatively quickly and 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 PoW systems, while achieving a high throughput of 10000 transactions per second.

Category / Keywords: applications / Blockchain; cryptocurrency; blockchain consensus.

Date: received 2 Mar 2018, last revised 13 Jun 2018

Contact author: j yu research at gmail com

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Version: 20180613:133436 (All versions of this report)

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