With the emergence of new technologies such as cloud computing and the Internet of Things (IoT), the term "zero trust" is gaining more attention. Modern cybersecurity threats and network attacks are becoming increasingly complex and covert, and traditional security models are no longer able to cope with these new challenges. Zero trust has become a prominent cybersecurity concept that can combine various security technologies and control measures to achieve comprehensive network security monitoring and threat response.

However, zero trust is not a new concept, as experts proposed the idea as early as 2010. Before implementing zero trust, it is necessary to understand the current network environment and resources and assess the strength and weaknesses of existing defense measures to determine whether zero trust is needed. Therefore, what is needed is not just zero trust, but also a way to implement it. The ISA/IEC 62443 international standard provides a comprehensive set of methods for implementing zero trust.