Combinatorial Optimization for Efficient and Trustful Blockchain

Abstract

BlockChain (BC) is a specially designed distributed public data structure, maintained without any third party of absolute trust by the so-called consensus protocol. Besides the financial applications, BC can be utilized in different domains (digital identity, voting, IoT, insurance, healthcare, etc.). BC consists of a list of blocks containing data (referred to as "committed transactions") that are allowed to be added simultaneously. The main issues in maintaining BC are security, privacy, consistency, and reducing the consumption of electrical energy. We aim to contribute toward overcoming these issues by applying Artificial Intelligence (AI) tools. First we optimize usage of resources by developing a new consensus protocol, named Proof-of-Useful-Work (PoUW), based on combinatorial optimization (CO) that enables miners to be doubly rewarded: for creating blocks and solving submitted CO instances. The second contribution aims to improve security in BC by examining the anonymity level of the participants, having in mind that the corresponding transactions are usually publicly available. This task reduces to classification/clustering of transactions according to some criteria.