Blockchain technology based applications are emerging to establish distributed trust amongst organizations who want to share critical information for mutual benefit amongst their peers. There is a growing need for consortium based blockchain schemes that avoid issues such as false reporting and free riding that impact cooperative behavior between multiple domains/entities. Specifically, customizable mechanisms need to be developed to setup and manage consortiums with economic models and cloud-based data storage schemes to suit various application requirements. In this MS Thesis, we address the above issues by proposing a novel consortium blockchain architecture and related protocols that allow critical information sharing using a reputation system that manages co-operation amongst peers using off-chain cloud data storage and on-chain transaction records. We show the effectiveness of our consortium blockchain management approach for two use cases: (i) threat information sharing for cyber defense collaboration system viz., DefenseChain, and (ii) protected data sharing in healthcare information system viz., HonestChain. DefenseChain features a consortium Blockchain architecture to obtain threat data and select suitable peers to help with cyber attack (e.g., DDoS, Advance Persistent Threat, Cryptojacking) detection and mitigation. As part of DefenseChain, we propose a novel economic model for creation and sustenance of the consortium with peers through a reputation estimation scheme that uses 'Quality of Detection' and 'Quality of Mitigation' metrics. Similarly, HonestChain features a consortium Blockchain architecture to allow protected data sharing between multiple domains/entities (e.g., health data service providers, hospitals and research labs) with incentives and in a standards-compliant manner (e.g., HIPAA, common data model) to enable predictive healthcare analytics. Using an OpenCloud testbed with configurations with Hyperledger Composer as well as a simulation setup, our evaluation experiments for DefenseChain and HonestChain show that our reputation system outperforms state-of-the-art solutions and our consortium blockchain approach is highly scalableIncludes bibliographical references (pages 45-52)
