A Secure Contact Tracing Method Using Blockchain for Criminal Investigation
Mizuki Tsuchida, Kazumasa Omote · 2024
The global outbreak of new coronavirus infections has increased the demand for smartphone-based contact tracing. In particular, much research has been conducted on contact tracing using blockchain, which is decentralized and hard to tamper with data. However, contact tracing requires the centralized collection of information for tracing users, and this essence remains the same even when using blockchain. In this study, we propose a blockchain-based contact tracing method that mitigates the centralized information collection and considers user privacy so that the administrator cannot trace the information. In this scheme, only the application knows the wallet address corresponding to the user, so even the trust authority cannot determine the user's identity from the wallet address. This method is capable of notifying users who may be witnesses at a crime scene by using smart contracts. Users can also prove their innocence if suspected of a crime. Furthermore, we will demonstrate the effectiveness of this method by conducting a demonstration experiment using an Ethereum testnet and two smartphones.