A New Distributed, Decentralized Privacy-Preserving ID Registration System

Abstract

Blockchain, a distributed ledger technology, is used in various fields, including many types of critical infrastructure, such as smart grids. Recently, studies have dealt with privacy preservation in smart grids. One such study presented a privacy-preserving aggregation system that provides integrity and anonymity using blockchain technology in a smart grid. In earlier work, a Bloom filter was used for rapid authentication on the blockchain, and a key management center was used for user key management. However, due to its high dependence on the key management center, it was not able to provide a completely distributed environment, and there was a linkability problem. In addition, there was a limitation in that key revocation and update functions through the Bloom filter could not be provided. In this article, we propose a decentralized privacy-preserving ID scheme that provides a fully distributed environment to address the limitations of existing research. The proposed scheme provides unlinkability to protect the anonymity of users using a blind signature. It also provides update or revocation functionalities of the pseudonym by the counting Bloom filter or the revoked-pseudonym Bloom filter. In addition, fully distributed operation is guaranteed through the certification authority responsible for user key management. Our scheme is applicable not only to blockchain-based decentralized privacy-preserving systems such as billing systems in a smart grid or smart cities, but also to any critical infrastructure, such as banks, hospitals, and systems including e-bulletins, e-surveys, e-voting, and so on.