Our new publication “A Security Property Decomposition Argument Pattern for Structured Assurance Case Models” is now published online.  In this paper, we propose a security assurance argument pattern called Security Property Decomposition. This pattern is extracted by studying existing security assurance case models and their decomposition to argue the satisfaction of security properties such as confidentiality, integrity, and availability. It also considers the requirements prescribed by several prominent security standards for developing secure and trustworthy systems in different application domains. It was presented at the 26th European Conference on Pattern Languages of Programs (EuroPLoP 2021) in July 2021. See Publications for more details!