Efficient Key Rotation for Blockchain-Based Self-Sovereign Identity

Abstract

Traditional digital identity models suffer from certain vulnerabilities in terms of identity reusability and privacy, as well as a single point of failure. The emergence of the blockchainbased self-sovereign identity model holds promise for addressing these issues in traditional digital identity models. However, existing schemes not only fail to cover privacy preservation throughout the entire lifecycle of credential issuance, verification, and revocation but also present security and efficiency concerns in key rotation. In this paper, we propose a novel blockchain-based self-sovereign identity system and redesign its credential scheme and key rotation mechanism. By leveraging the PS signature and zero-knowledge proof, our scheme preserves the privacy of holders’ private attributes when issuing and verifying credentials. Additionally, with the cryptographic accumulator, our scheme does not reveal any issued or revoked credentials. Furthermore, we propose a secure and efficient key rotation mechanism based on pre-generated key chains, which enables secure and efficient key rotation without relying on a timelock. Finally, we provide a security analysis and performance evaluation, demonstrating the security and practicality of our scheme.