Chi-Kin Chau

Traditional Insurance, a popular approach of financial risk management, has suffered from the issues of high operational costs, opaqueness, inefficiency and a lack of trust. Recently, blockchain-enabled parametric insurance through authorized data sources (e.g., remote sensing and IoT) aims to overcome these issues by automating the underwriting and claim processes of insurance policies on a blockchain. However, the openness of blockchain platforms raises a concern of user privacy, as the private user data in insurance claims on a blockchain may be exposed to outsiders. In this paper, we propose a privacy-preserving parametric insurance framework based on succinct zero-knowledge proofs (zk-SNARKs), whereby an insuree submits a zero-knowledge proof (without revealing any private data) for the validity of an insurance claim and the authenticity of its data sources to a blockchain for transparent verification. Moreover, we extend the recent zk-SNARKs to support robust privacy protection for multiple heterogeneous data sources and improve its efficiency to cut the incurred gas cost by 80%. As a proof-of-concept, we implemented a working prototype of bushfire parametric insurance on real-world blockchain platform Ethereum, and present extensive empirical evaluations.

Retail energy markets are increasingly consumer-oriented, thanks to a growing number of energy plans offered by a plethora of energy suppliers, retailers and intermediaries. To maximize the benefits of competitive retail energy markets, group purchasing is an emerging paradigm that aggregates consumers' purchasing power by coordinating switch decisions to specific energy providers for discounted energy plans. Traditionally, group purchasing is mediated by a trusted third-party, which suffers from the lack of privacy and transparency. In this paper, we introduce a novel paradigm of decentralized privacy-preserving group purchasing, empowered by privacy-preserving blockchain and secure multi-party computation, to enable users to form a coalition for coordinated switch decisions in a decentralized manner, without a trusted third-party. The coordinated switch decisions are determined by a competitive online algorithm, based on users' private consumption data and current energy plan tariffs. Remarkably, no private user consumption data will be revealed to others in the online decision-making process, which is carried out in a transparently verifiable manner to eliminate frauds from dishonest users and supports fair mutual compensations by sharing the switching costs to incentivize group purchasing. We implemented our decentralized group purchasing solution as a smart contract on Solidity-supported blockchain platform (e.g., Ethereum), and provide extensive empirical evaluation.

Smart inverters have evolved from performing basic DC/AC electrical conversion to complex interconnected active grid integration and stabilization functions. Although there has been increasing regulation on the electrical compliance of smart inverters, compliance efforts for their cybersecurity are lacking. In this article, we provide a systematic study of aspects of smart inverters that pose cybersecurity threats, and discuss the challenges and potential solutions to mitigate these threats. Our findings underscores the urgent need for enhanced cybersecurity measures to protect smart inverters from emerging threats and ensure grid stability.

P2P energy trading allows direct energy transactions among end users to maximize the benefits of distributed energy resources. Permissionless blockchain platforms (e.g., Ethereum) facilitate P2P energy trading through energy credit tokenization, such that users who export energy to the grid will receive the respective energy credit tokens on Ethereum that can be traded in a P2P fashion without an intermediary. Despite the benefits of P2P trading on a trustless open platform, blockchain-enabled P2P energy trading suffers from a number of practical issues, such as slow transaction confirmation time, poor scalability, high transaction fees for micro-transactions, and the need for persistent connections to the blockchain. Hence, we develop an off-chain payment solution to allow trustless off-chain transactions of energy credit tokens, in the similar vein as popular off-chain payment channel networks for Bitcoin cryptocurrencies (e.g., Lightning Network). But unlike typical cryptocurrencies, off-chain trading of energy credit tokens faces new challenges. Particularly, energy credit tokens are essentially future commodities that are generated ex-post from delayed smart meter reporting. It is challenging to support real-time P2P energy trading with future energy credit tokens that are not yet generated at the moment of trading, which significantly increases the counterparty risks among untrusted users. In this paper, we design EnergiPay, a secure off-chain payment channel protocol to mitigate the counterparty risks in off-chain P2P energy trading.