Blockchain is a novel way to construct fully distributed systems and has the potential to disrupt many businesses including Uber and Airbnb within the sharing economy. Specifically, blockchain provides a method to enforce the agreement between a user and the physical property owner without using any trusted party, e.g., if a user pays the agreed money, the blockchain guarantees that he/she has access to the property. While a blockchain based system has many desirable features, it may leak privacy information of involved parties due to its openness to the public. To mitigate the privacy concern, we propose a privacy respecting approach for blockchain-based sharing economy applications, which leverages a zero-knowledge scheme. We also analyze the security features and performance of the proposed approach to demonstrate its effectiveness in these applications.

E-government system has greatly improved the efficiency and transparency of daily operations of a government. However, most of existing e-government services are provided in a centralized manner and heavily rely on human individuals to control. The highly centralized IT infrastructure is more vulnerable to outside attacks. Also, it is relatively easy to compromise the data integrity by inside rogue users. Furthermore, relying on individuals to monitor and control some of the working flows makes the system error-prone and leaves room for corruption. To address these challenges, we propose to use the blockchain technology and decentralized autonomous organization (DAO) to improve the e-government system. The blockchain-based DAO system works in a fully decentralized way and is immune to both outside and inside attacks. At the same time, operations of such system is only controlled by pre-defined rules; thus, the uncertainty and errors caused by human processes are greatly reduced. We provide a concrete use case to demonstrate the usage of DAO e-government and evaluate its effectiveness.