ReviewChain: Smart Contract Based Review System with Multi-Blockchain Gateway

A review system is a valuable component in E-commerce applications. Existing centralized review systems are prone to review frauds and manipulations. A decentralized, immutable and auditable blockchain system is a natural fit to prevent fraudulent and manipulated reviews. We develop and implement ReviewChain, a decentralized review system using Ethereum smart contract. ReviewChain validates new reviews by querying the identity of purchasers from a supply chain system. We assume that the supply chain system is based on blockchain technology. We develop and implement a mechanism to tie two disparate Ethereum based blockchain networks. Ethereum smart contract code is limited and cannot make external procedure calls. Therefore, we introduce multi-blockchain gateway nodes called notaries. Our proposed smart contracts and notaries allow us to interface two blockchains effectively. We run ReviewChain and discuss how various design parameters impact the system performance.