Incentives for Stable Mining in Pay Per Last N Shares Pools

A large number of blockchain consensus protocols 7 use the Proof of Work (PoW) principle, which relies on miners who exchange computation for newly minted currency. Their) task is to support consensus, safeguarding the immutability of the chain's history. For the sake of regular income, a vast majority of miners team-up in large independent pools. These pools distribute among all their members the rewards gathered from individual miners, thus guaranteeing a stable income for each miner in the pool. The monetary compensation follows a specific reward system enforced by the pool administrator. Pay Per Last N Shares (PPLNS) is one of the most popular reward systems in PoW pools. Despite many desirable properties, in this paper, we show that composition of PPLNS pools may be unstable. To better understand the incentives of miners, we explore the effect of time preferences in the mining decisions of miners. Using a) game-theoretical model we study conditions for equilibrium in a) game with two different PPLNS pools. We find that the range of parameters that support equilibria between the pools with large number of miners is minuscule. This implies that in many cases, miners may have incentives to migrate towards larger pools, harming decentralization in the process. I

[1]  Tim Roughgarden,et al.  Incentive Compatibility of Bitcoin Mining Pool Reward Functions , 2016, Financial Cryptography.

[2]  Reza Pulungan,et al.  Time-Dependent Analysis of Attacks , 2014, POST.

[3]  Krishnendu Chatterjee,et al.  Ergodic Mean-Payoff Games for the Analysis of Attacks in Crypto-Currencies , 2018, CONCUR.

[4]  Jeffrey S. Rosenschein,et al.  Bitcoin Mining Pools: A Cooperative Game Theoretic Analysis , 2015, AAMAS.

[5]  Abhi Shelat,et al.  Socially Optimal Mining Pools , 2017, WINE.

[6]  Satoshi Nakamoto.  Bitcoin : A Peer-to-Peer Electronic Cash System , 2009 .

[7]  Yongdae Kim,et al.  Be Selfish and Avoid Dilemmas: Fork After Withholding (FAW) Attacks on Bitcoin , 2017, CCS.

[8]  Sam M. Werner,et al.  Swimming with Fishes and Sharks: Beneath the Surface of Queue-Based Ethereum Mining Pools , 2017, 2017 IEEE 25th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS).

[9]  Fei-Yue Wang,et al.  Economic Issues in Bitcoin Mining and Blockchain Research , 2018, 2018 IEEE Intelligent Vehicles Symposium (IV).

[10]  G. Bolton.  Reliability , 2003, Medical Humanities.

[11]  Erik Angner,et al.  A Course in Behavioral Economics , 2012 .

[12]  Ittay Eyal,et al.  The Miner's Dilemma , 2014, 2015 IEEE Symposium on Security and Privacy.

[13]  Stefan Dziembowski,et al.  Introduction to Cryptocurrencies , 2015, CCS.

[14]  Meni Rosenfeld,et al.  Analysis of Bitcoin Pooled Mining Reward Systems , 2011, ArXiv.

[15]  Weijia Jia,et al.  On the Strategy and Behavior of Bitcoin Mining with N-attackers , 2018, IACR Cryptol. ePrint Arch..

[16]  Carlo Kleber da Silva Rodrigues,et al.  Automatic hopping among pools and distributed applications in the Bitcoin network , 2016 .