NSSIM: A Novel Self-Sovereign Identity Scheme For Metaverse with Sybil-Resistance, Full Lifecycle Synchronization and Joint Accountability

Abstract The metaverse is a promising internet and social formation that aims to achieve a high level of synchronization and indivisibility between the virtual and physical worlds. In the ultimate stage of metaverse, a natural person acts as an avatar not only to conduct all kinds of activities across time and space in the virtual world but also to sense and change the physical world. Therefore, a genuine avatar serves as a trust anchor and is crucial for the organized advancement of the metaverse. Self-Sovereign Identity (SSI) is regarded as the promising scheme to build trust foundation for the metaverse, since it takes the trust anchor from a third-party organization back to a user, compared with the traditional digital identity management. Although the state-of-the-art SSI schemes already have appended the abilities of sybil-resistance, accountability, revocation or recovery, they suffer from privacy leakage and internal corruption due to a centralized authority involved. Futhermore, they failed to take into consideration high synchronization and indivisibility in metaverse. In order to construct a reliable and secure trust anchor for metaverse, a new self-sovereign identity scheme (NSSIM) with sybil-resistance, full lifecycle synchronization and joint accountability is proposed in this paper. Specifically, a genuine avatar generation protocol which provide one-to-one bound to a natural person is designed to achieve the sybil-resistance without violating privacy. And, an avatar behavior paradigm is devised to fulfill the full lifecycle synchronization between an avatar and the corresponding natural person, as well as protect his identity privacy. Furthermore, a joint accountability procedure is proposed to conduct fair, public and conditional regulation over avatar behavior paradigms. Finally, we analyze the security, properties of our scheme and conduct detailed experiments in term of the cost of computation and storage. The security analysis results indicate that our scheme resists all the known attacks. Compared with the state-of-the-art SSI schemes, our scheme fulfills all the SSI properties and the extensive experiment results show that the computation cost is small and the storage cost for privacy protection is acceptable.