  Digital Twins (DTs) are a conventional and well-known concept, proposed in
70s, that are popular in a broad spectrum of sciences, industry innovations,
and consortium alliances. However, in the last few years, the growth of digital
assets and online communications has attracted attention to DTs as highly
accurate twins of physical objects. Metaverse, as a digital world, is a concept
proposed in 1992 and has also become a popular paradigm and hot topic in public
where DTs can play critical roles. This study first presents definitions,
applications, and general challenges of DT and Metaverse. It then offers a
three-layer architecture linking the physical world to the Metaverse through a
user interface. Further, it investigates the security and privacy challenges of
using DTs in Metaverse. Finally, a conclusion, including possible solutions for
mentioned challenges and future works, will be provided.
