# A Survey of the Real-Time Metaverse: Challenges and Opportunities +
## 3 Key Enabling Technologies: An Overview
Innovations such as the FingerTac haptic gloves provide real-time haptic feedback and improve the realism of AR applications [9]. The infrastructure supporting the metaverse must handle compute- and data-intensive tasks efficiently. Research has demonstrated that the application of VR combined with treadmill training can improve balance and mobility in individuals with traumatic brain injury (TBI) [64]. The integration of VR in rehabilitation highlights its potential in the metaverse, where real-time feedback and dynamic interaction are key. The study showed that participants engagedmore with the VR-assisted training, reporting improved balance and mobility [65]. This aligns with the metaverse's vision of creating adaptive and immersive spaces customized to individual user needs, whether for entertainment, social interaction, or healthcare. The above research underscores VR's transformative potential, especially in healthcare applications within the metaverse [66]. By offering real-time sensory feedback and stimulating neural pathways, as seen in neurorehabilitation, VR in the metaverse can provide personalized and therapeutic environments for users [67]. Therapeutic applications can have significant implications, particularly for industries such as healthcare, where virtual environments could be used for rehabilitation [68], therapy [69], and patient care [70]. Additionally, by enabling real-time interaction and multisensory engagement, VR enhances the immersive potential of the metaverse applications, making them more impactful and effective. The study on virtual taste and smell technologies further expands the sensory dimensions of VR, which is essential for a more immersive metaverse experience [71]. By integrating taste and smell, the metaverse can replicate real-world environments with a higher level of fidelity, crucial for applications in sectors such as education [72], gaming [72], and virtual tourism [73]. These technologies can enrich user experiences, offering deeper emotional and cognitive connections to the virtual world, which could be used in leisure and therapeutic contexts. Developing multisensory technologies, such as taste and smell in VR, is essential for expanding the metaverse's immersive capabilities [74; 75]. Incorporating sensory feedback beyond visual and auditory stimuli could transform user experiences across various applications, from entertainment to education and healthcare [76]. By enhancing the multisensory engagement, the metaverse can simulate real-world interactions more effectively, providing users with a richer, more connected virtual experience. Moreover, research into VR's potential in therapeutic settings showcases the broader applications of immersive virtual worlds. The metaverse could provide virtual spaces where patients receive specialized, personalized treatment plans, leveraging VR's ability to simulate realistic environments and offer real-time sensory feedback [77]. _Security_ and _privacy_ are among the top concerns in the metaverse, where vast amounts of personal data and digital assets are exchanged [78]. The immersive and persistent nature of the metaverse magnifies these concerns, as users' real-world identities, behaviors, and biometric data, such as eye movements or facial expressions, may be tracked and stored [21]. The importance of advanced cryptographic algorithms and robust security protocols to protect user data and ensure secure transactions is a fundamental requirement [79]. Also, zero-knowledge proofs and homomorphic encryption are receiving more attention as possible ways to keep private user data safe while still allowing transactions to happen without trust [80; 81]. Some research explains that the decentralized nature of the metaverse offers a layer of security by eliminating the need for a central authority [17; 82]. However, decentralization also presents challenges, particularly in maintaining data integrity and preventing unauthorized access.