Vehicle Routing Based Mining for Proof-of-Useful-Work Blockchain

Abstract

Blockchain gains tremendous attraction recently as the appearance of cryptocurrencies that can serve as an alternative of transaction between two entities that does not require a third party to intermediate the transaction. Blockchain is designed as an immutable digital ledger, consisting of a chain of blocks, with each block storing the information of transactions that happened between nodes in the blockchain network. Proof-of-Work (PoW) is the most popular consensus protocol to mine blocks in public blockchain, where participating nodes (miners) will use its computation resource to solve computational problems. However, the problems being solved in many PoW blockchains can be considered not useful, as they are designed to have high complexity but the output does not exactly serve any meaningful purpose, leading to massive energy waste. Proof-of-Useful-Work (PoUW) is a variant of PoW, where the miners mine blocks by solving more useful problems, having a more meaningful purpose for the output. This paper proposes the optimization of the Vehicle Routing Problem (VRP) as a block mining mechanism for PoUW blockchain. The proposed PoUW produces a new block by having miners solve VRP instances competitively. Particle Swarm Optimization (PSO) is used by miners to solve the VRP instance. The VRP instances are provided by external parties that also provide rewards for successfully mining the new block. The proposed PoUW blockchain can convert the computational effort to solve more useful problems, which serve a better purpose for the spent energy.