Six years have passed since the successful Nuclear Security Summit Process was completed. Since then, the momentum for strengthening nuclear security is gradually diminishing. On the other hand, under the COVID-19 pandemic, telework and web-based meeting are rapidly increasing, and it is necessary to respond to new threats such as cyber security. There were cases of insufficient physical protection measures for nuclear material and facilities mainly due to the lack of a nuclear security culture. The international community has made good use of the review conference of the Amended Convention on the Physical Protection of Nuclear Material to revitalize the momentum for strengthening nuclear security. The responsibility of ensuring nuclear security within a State rests entirely with that State. Each State needs to grasp the overall picture of its own nuclear security regime, identify the gaps in infrastructure development, and fill the gaps. ISCN/JAEA proposes Nuclear Security Stakeholder Matrices (NSSHM) for that purpose. The 1540 Committee has also attempted to use similar matrices to strengthen the spread of weapons of mass destruction. The NSSHM identifies all agencies involved in nuclear security regime in a State, their responsibilities, and the knowledge and skills to fulfill such responsibilities. Through the development of matrices table, it enables a State to clarify the missing link as well as overlaps, so that a State will be able to fill the gaps. NSSHM can also be used to design the capacity building plan including training and education. NSSHM will be the powerful tool to strengthen the nuclear security Regime of each State more systematically. If the relevant organizations can work together to develop and use NSSHM, it will be possible to effectively and efficiently enhance nuclear security regime. This paper will report the results of the Nuclear Security Stakeholder Matrices Project being implemented in the FNCA Nuclear Security and Safeguards Project.