# Blockchain-Enabled Secure and Interoperable Authentication Scheme for Metaverse Environments
###### Abstract  
The metaverse, which amalgamates physical and virtual realms for diverse social activities, has been the focus of extensive application development by organizations, research institutes, and companies. However, these applications are often isolated, employing distinct authentication methods across platforms. Achieving interoperable authentication is crucial for when avatars traverse different metaverses to mitigate security concerns like impersonation, mutual authentication, replay, and server spoofing. To address these issues, we propose a blockchain-enabled secure and interoperable authentication scheme. This mechanism uniquely identifies users in the physical world as well as avatars, facilitating seamless navigation across verses. Our proposal is substantiated through informal security analyses, employing automated verification of internet security protocols and applications (AVISPA), the real-or-random (ROR) model, and Burrows-Abadi-Needham (BAN) logic and showcasing effectiveness against a broad spectrum of security threats. Comparative assessments against similar schemes demonstrate our solution's superiority in terms of communication costs, computation costs, and security features. Consequently, our blockchain-enabled, interoperable, and secure authentication scheme stands as a robust solution for ensuring security in metaverse environments. authentication; metaverse; blockchain; interoperability; decentralized identity; security +
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Within the metaverse, users generate virtual avatars as digital representations of themselves, enabling access to various services. However, the current metaverse allows users to create avatars without real-world identity verification, opening possibilities for malicious activities such as identity theft, impersonation, replay, server spoofing, replay-virtual-asset fraud, stalking, and privacy threats. Users also exchange information with third parties, but unmapped identities pose challenges. For dealing with unmapped identities, maintaining consistency between virtual and physical identities is crucial. A robust authentication scheme is essential to ensure user safety, especially given the lack of direct means for users to verify avatar identities [3; 4]. The existing metaverse platforms rely on passwords, making them vulnerable, and providing extensive personal information to service providers poses privacy risks. Moreover, these platforms provide avatar authentication in silos although it is centralized in nature. The authentication mechanism in one platform is completely different from that in another platform. So, there is a need for interoperable identity mechanisms. If an avatar wants to traverse from one virtual world to another, then the different identity mechanisms used by different platforms affects the immersive experience, making interoperability impossible [5]. In addition, there is no mapping available between a physical-user identity and an avatar identity in a virtual world. Considering all of these challenges, there is a serious need to implement a decentralized and interoperable identity mechanism that will address identity-related security issues such as impersonation, replay, server spoofing, mutual authentication, man-in-the-middle attack, etc. [6; 7]. To address these issues, in this paper we propose a blockchain-enabled secure and interoperable authentication scheme to enhance security and protect users from diverse identity-related threats. Blockchain is a decentralized ledger technology that enables users to store transactions in a block in an immutable way. Each block is connected to the next one to form a chain of blocks. The blockchain is constructed through the linkage of blocks, which is achieved by storing the hash of the previous block in the subsequent one. Originating with the inception of Bitcoin, blockchain technology has found application in diverse scenarios.