Greedy-Mine: Bitcoin-NG is Not Incentive Compatible

EasyChair Preprint 9744

Abstract

Bitcoin-NG is an extensible blockchain protocol based on the same trust model as Bitcoin. It divides each epoch into one Key-Block and multiple Micro-Blocks, effectively improving transaction processing capacity. Bitcoin-NG a special incentive mechanism (i.e., the transaction fees in each epoch are split to the current and next leader) to maintain its security. The incentive division method of Bitcoin-NG only includes some specific mining attack strategies of adversary, while ignoring the greedy attack strategy.  We propose a Greedy-Mine attack strategy and prove that Bitcoin-NG mining is incentive incompatible. we summarize the computing power proportion range required for malicious adversaries to launch Greedy-Mine to obtain excess returns. we make a backward-compatibility progressive modification to Bitcoin-NG protocol that would raise the threshold of propagation factor from zero to 1. Our analytical and simulation results indicate that Bitcoin-NG mining is not incentive compatible, and Bitcoin-NG is vulnerable to Greedy-Mine attack.

Keyphrases: Blockchain, Markov reward model, Mining Strategy, incentive mechanism

@booklet{EasyChair:9744,
  author    = {Junjie Hu and Chunxiang Xu},
  title     = {Greedy-Mine: Bitcoin-NG is Not Incentive Compatible},
  howpublished = {EasyChair Preprint 9744},
  year      = {EasyChair, 2023}}