Best Practices for Developing Safe and Secure Modular Software

This white paper discusses best practices for developing safe and secure modular software, particularly in the context of aerospace and defense industries. It emphasizes the importance of a Modular Open Systems Approach (MOSA), which promotes modularity, interoperability, and the use of open standards. The paper outlines how MOSA can enhance the adaptability of software components while also addressing the unique challenges related to safety and security. It details various civilian and defense standards that support modular design, including RTCA/DO-297, FAA AC 20-170, RTCA/DO-178C, and ARINC 653. These standards provide guidance for the development, verification, and certification of modular software systems. The document also highlights the economic advantages of modular design, such as cost reduction and design flexibility, while underscoring the necessity for compliance with functional safety and security standards. The paper serves as a comprehensive resource for organizations looking to implement effective modular software development practices.