Counterfactual Quantum Byzantine Consensus for Human-Centric Metaverse

Quantum Byzantine fault tolerance (BFT) consensus is a secure and reliable mechanism that enables network nodes to reach an agreement even in the presence of faulty nodes, by using distributed private correlated lists. It plays a crucial role in developing the blockchain-based Metaverse to ensure its integrity and security. In this paper, we propose a counterfactual quantum BFT (CQ-BFT) protocol for a multipartite network using counterfactual unitary telecomputation with the chained quantum Zeno gates. This consensus protocol achieves an agreement among the parties without the passage of any physical particles through the quantum channel. Due to the unique properties of counterfactual communication, we demonstrate that the CQ-BFT protocol can operate in the absence of a shared phase reference and provide a quantum layer of security and robustness against dephasing noise, fulfilling the stringent requirements of blockchain technology. In addition, we analyze the performance tradeoff of the CQ-BFT protocol in terms of the three pillars of blockchain—i.e., security, scalability, and decentralization. The human-centric Metaverse could leverage high degrees of security, noise resilience, and fault tolerance of the CQ-BFT protocol to enhance its underlying network infrastructure. This protocol leads to more robust and immersive virtual environments that prioritize the needs and experiences of Metaverse users.

I. Introduction

Metaverse, the convergence of physical and digital realities towards the virtual world, has recently become of great interest in the technological industry and research community [1]. The emergence of the Metaverse has been facilitated by the rapid advancements of blockchain, augmented reality, virtual reality, the Internet of Things, and distributed computing [2]. Recently, Facebook Inc. has rebranded itself as “Meta” to accelerate the realization of the Metaverse. This transformation aims to create an immersive environment where people can surpass their own personal and career growth expectations. Initially, the concept of Metaverse was focused on the convergence of physical and digital realities with less realizing the needs and interests of human beings. Later, the concept of a human-centric Metaverse has been introduced, which emphasizes the concerns of human beings. The ultimate goal is to enhance and enrich human lives with meaningful customized experiences. By prioritizing the human aspect, the human-centric Metaverse aims to create a user-centered virtual realm that provides valuable experiences and opportunities [3].