Conquering Generals

Abstract

Proof of Work systems are used in cryptocurrencies to obtain consensus in distributed peer-to-peer systems that share no trust. Miners of cryptocurrency compete by engaging in the Proof of Work to solve a cryptographic challenge. The first to successfully provide a solution to the challenge wins by minting new currency. The process of mining also simultaneously prevents double-spending through the creation of an append-only distributed database known as the blockchain. The most widely adopted Proof of Work is the Hashcash scheme and the most widely deployed miners are ASIC-based. Despite the popularity of Hashcash, two issues are commonly identified its use. Firstly, the high energy consumption of the scheme is perceived as wasteful because the solutions found provide no useful output, and secondly, the computational complexity class of the scheme is not formally known. Based on these deficiencies, we propose a novel Proof of Work system which achieves the following goals: