The document outlines a security model for Data Distribution Service (DDS) focusing on confidentiality, integrity, authentication, and authorization within distributed systems. It introduces mechanisms for transport security, specifically through the use of Secure Real-time Transport Protocol (SRTP) and Multimedia Internet Keying (MIKEY) for key distribution, while emphasizing composable security levels at both topic and attribute levels. The next steps include detailing the implementation of these security features and finalizing the API for security plugins.