In today's rapidly evolving digital landscape, High-Performance Computing (HPC) has become a core technology across various fields, from scientific research to financial analysis, all relying on its powerful computational capabilities. However, with technological advancements, security threats have also grown increasingly complex, highlighting the importance of a thorough examination of the security of HPC environments. This presentation will focus on the NIST SP 800-223 standard, providing an in-depth analysis of the security architecture, threat assessment, and security posture of high-performance computing. The talk will cover the background of NIST SP 800-223 and its significance in HPC security, followed by a discussion on how to establish a robust security architecture to guard against various potential threats. Subsequently, we will delve into the major security threats currently facing HPC environments, including the characteristics and impacts of both internal and external attacks, and offer effective countermeasures. Additionally, the presentation will emphasize the concept of security posture, exploring how organizations can assess and enhance their protective capabilities within high-performance computing.