SAGTM: A secure authentication scheme with traceability for avatars in the Metaverse

Abstract

The Metaverse, by integrating virtual and physical worlds, offers a digital platform that transcends the limitations of time and space, enabling users to engage in entertainment, work, and social interactions. However, these applications also introduce privacy risks, making robust identity authentication systems crucial. Traditional security measures are inefficient and inadequate for the unique requirements of Metaverse environments. The anonymous credential scheme, as a method of anonymous authentication, can effectively prevent attackers from accessing avatar information while ensuring that the accessing server cannot identify the avatar, thereby protecting avatar privacy. Moreover, it facilitates the tracking and management of malicious avatar behavior. Towards this advanced goal, this work proposes a blockchain-based supervised authentication scheme using anonymous credentials. Firstly, non-interactive zero-knowledge proofs are integrated into anonymous credentials technology to achieve avatar anonmity and unlinkability. Secondly, the distributed ElGamal encryption algorithm is used to enable traceability for locating malicious users. Finally, to verify the avatar’s access permission, the proposed scheme combines an accumulator into blockchain technology, enabling the access server to verify the level of access while maintaining anonymity and unlinkability. Security analysis demonstrates that our scheme possesses advantages such as traceability, unlinkability, anonymity, and forgery resistance. Experimental results indicate that the proposed scheme outperforms other anonymous authentication schemes in terms of performance overhead. Therefore, our scheme is more efficient and practical compared to other anonymous schemes.