Design of Blockchain-Enabled Secure Real Life Applications/ Debendranath Das

Thesis (Ph.D) - Indian Statistical Institute, 2024

Includes bibliography

Introduction -- Preliminaries and Background -- Blockchain-Enabled Secure and Smart Healthcare System -- Blockchain-Enabled Secure Health Insurance Processing -- Blockchain-Enabled Secure Vaccine Passport System -- Blockchain-Enabled Secure Payment Card Tokenization System -- Blockchain-Enabled Multicurrency Supported Distributed e-Banking System -- Conclusion

Guided by Dr. Sushmita Ruj & Prof. Subhamoy Maitra

Blockchain is a distributed, immutable, verifiable append-only ledger maintained across a peer-to-peer network. Bitcoin, proposed by Satoshi Nakamoto in 2008, is the first and most popular application based on blockchain technology, enabling digital transactions using a virtual currency called Bitcoin. In 2015, Ethereum, the next famous permission-less blockchain platform, supported writing smart contracts using a Turing-complete language. This allows developers to build any secure decentralized application on the platform. In this thesis, we propose and implement several secure protocols applicable to various real-life applications, specifically focusing on the healthcare and banking sectors. These works leverage the power of the Ethereum blockchain, smart contracts, and relevant cryptographic tools. All our prototypes are implemented using the Ethereum platform: the first two were deployed on the Ropsten test network, and the remaining on the Sepolia test network. Our first contribution proposed a blockchain-enabled secure and smart healthcare system, where blockchain integrated with smart contracts builds trust by providing transparency. The system guarantees fairness between the patient and the hospital, as well as the privacy and security of the patient’s electronic healthcare records (EHRs). The second proposal extends the scope of the first by introducing a novel blockchain-enabled health insurance processing system that streamlines critical operations and ensures fairness for all stakeholders. Various insurance procedures are encoded through smart contracts, increasing transparency and trust in the claim settlement process. We present a secure and privacy-preserving access control policy for sharing EHR with insurance companies during verification to address privacy concerns. A Vaccine Passport provides proof of vaccination, enabling mobility during pandemics like COVID-19. Challenges include preventing certificate forgery and protecting personal data. As our third contribution, we propose a blockchainenabled vaccine passport system powered by smart contracts, ensuring secure and authentic vaccination certificates, with encrypted passports stored in the distributed InterPlanetary File System for added security. The current payment card tokenization landscape is dominated by centralized entities like Visa and Mastercard, serving as Token Service Providers (TSPs). Our fourth contribution introduces a decentralized blockchain-powered tokenization system, where smart contracts generate tokens based on predefined criteria, ensuring robustness and transparent audit trails. Finally, our fifth contribution is an innovative e-banking system leveraging blockchain’s decentralized features to support both fiat currencies and cryptocurrencies. Using Ethereum smart contracts, the system enables a single account to hold multiple currencies, with a functional prototype demonstrating its feasibility.