A Simple and Flexible Global ID System for Authentication in Blockchain

Abstract

In recent years, decentralized global ID systems have attracted significant attention. The concept of self-sovereign identity was established to realize a decentralized global ID, which is achieved by verifiable credentials and decentralized identifiers. However, there is a problem in using such decentralized global IDs for various remote services from the viewpoint of flexibility. In this paper, we propose a system which can give an "attribute" to global IDs dynamically by using only the basic function of a blockchain (i.e., using cryptocurrency transfer only). The main idea of our scheme is that an "attribute token" is assigned to global IDs or removed from global IDs using the token transmission function in a blockchain. Thus, we can set the credibility level and decentralization level of global IDs adaptively, and thus, we manage global IDs securely and flexibly. Furthermore, we conduct feasibility experiments with the proposed system and realize an attribute token assignment in Bitcoin and Ethereum cryptocurrencies. This result shows that our system can use almost all blockchain systems having a token transmission function.