Linking Souls to Humans: Blockchain Accounts with Credible Anonymity for Web 3.0 Decentralized Identity

TL;DR

This paper addresses the gap in Web 3.0 identity where fully anonymous blockchain accounts fail to reflect human social relationships. It introduces zkBID, a decentralized scheme that credibly links each verified human identity (PHC/VC) to a unique blockchain soul account using zero-knowledge proofs and linkable ring signatures, preserving privacy while ensuring one-to-one mappings. The design combines PHCs, Groth16-based zkSNARKs, and MLSAGS to enable on-chain identity verification (IVAC) and soul account certification, with a fully on-chain, user-generated data model. Experimental evaluation on a six-node Ethereum test network shows practical ZK proof sizes, verification costs, and ring-signature performance, illustrating zkBID’s feasibility and parameter-tuning guidance for real deployments.

Abstract

A decentralized identity system that can provide users with self-sovereign digital identities to facilitate complete control over their own data is paramount to Web 3.0. The account system on blockchain is an ideal archetype for realizing Web 3.0 decentralized identity. However, a disadvantage of such completely anonymous identity system is that users can create multiple accounts without authentication to obfuscate their activities on the blockchain. In particular, the current anonymous blockchain account system cannot accurately register the social relationships and interactions between real human users, given the amorphous mappings between users and blockchain identities. This work proposes zkBID, a zero-knowledge blockchain-account-based Web 3.0 decentralized identity scheme, to overcome endemic mistrust in blockchain account systems. zkBID links souls (blockchain accounts) to humans (users' personhood credentials) in a one-to-one manner to truly reflect the social relationships and interactions between humans on the blockchain. zkBID conceals the one-to-one relationships between blockchain accounts and users' personhood credentials for privacy protection using zero-knowledge proofs and linkable ring signatures. Thus, with zkBID, the users' blockchain accounts are credibly anonymous. Importantly, zkBID is fully decentralized: all user-related data are generated by users and verified by smart contracts on the blockchain. We implemented zkBID and built a blockchain test network for evaluation purposes. Our tests demonstrate the effectiveness of zkBID and suggest proper ways to configure zkBID system parameters.

Figures (6)

• Figure 1: The mapping relationship between the user identity (the PHC and its hash), and the seed public key, and the soul account.
• Figure 2: The overall operational flow of the IVAC process.
• Figure 3: An example of PHC designed in the form of VC.
• Figure 4: The block diagram of the arithmetic circuit in the zkSNRAK algorithm.
• Figure 5: The illustration of the generation and verification process of a linkable ring signature.