A Systematic Review of Digital Twins and Security for Cyber-Physical Systems

The rapid growth of Cyber-Physical Systems (CPS) has increased interest in digital twins (DTs) as virtual representations of physical systems to improve efficiency, monitoring, and security. However, as DTs become integral components of CPS, ensuring their own security also becomes critical. In this paper, we present a systematic literature review (SLR) on DTs and security for CPS. Following a standard SLR methodology, we defined three research questions, performed a structured search in four publication databases complemented by forward snowballing, applied inclusion and exclusion criteria, and extracted and synthesized data from the selected studies. The review examines both how DTs are used to enhance CPS security and how DTs themselves are secured within CPS. Our main results are: (i) a classification of CPS security challenges, threats, and vulnerabilities addressed using DTs; (ii) a mapping of security mechanisms, application domains, and emerging trends in using DTs for CPS security; (iii) a classification of DT security challenges, threats, and vulnerabilities across architectural, operational, data, and trust dimensions; (iv) a synthesis of state-of-the-art approaches for securing DTs; and (v) an analysis of open research problems and future directions for advancing both CPS security through DTs and the security of DTs themselves.