Blockchain applications beyond cryptocurrency

Abstract

Blockchain technology ensures immutability, transparency, and decentralization of transaction information. Originally designed to support cryptocurrency, blockchain technology has been integrated into applications in various domains. Yet, native adoption of blockchain technology may not fulfill all security requirements of the target applications. We realize that by integrating proper cryptographic primitives on top of the blockchain technology to some applications, the security and performance can be improved. In this thesis, we explore three different blockchain applications beyond cryptocurrency. We propose new designs with enhanced security and performance for each scenario. Specifically, we made the following contributions: (1) We proposed a blockchain-based e-voting system which does not rely on a single trusted party. The system achieves verifiability, eligibility, fairness, and anonymity. Specifically, we combined threshold cryptographic technique, ElGamal decryption scheme and blind signature to address the issues of single trusted party and efficiency. In addition, the time complexity of all voter functions is constant, which is efficient and practical for real-world scenario. (2) We proposed an efficient message authentication system for vehicular ad-hoc network (VANET) which allows revokable transparency, without requiring an online security mediator or an additional secure communication channel. In particular, we combined a new revocable signature scheme, KUNodes algorithm, cuckoo filter and blockchain technology to achieve the security, efficiency and functional requirements of our system. The proposed digital signature supports batch and online/offline verification. It also avoids the of digital use certificate and bilinear pairing for efficiency concerns. Besides, our experiment results also showed that our roadside unit (RSU) assisted signature verification protocol had a significant improvement on the overall efficiency. (3) We proposed an efficient blockchain-based supply chain management system for regulated industries. Our proposal scheme was based on practical settings and designs from the literature. In particular, we support four logistic behavioral patterns, quality management and different scenarios of tracing for regulation enforcement and anti-counterfeiting. In addition, we introduced a threshold twisted ElGamal decryption scheme for maintaining better privacy and auditability. Currently, our system has been deployed to and applied in pharmaceutical companies in China.