Secure by design is a proactive approach of cybersecurity that enables organizations to develop built-in security within their applications and infrastructures at the early stage of a development. It focuses on preventing cyberattacks rather than responding and restoring to security threats and incidents. And this principle requires organizations to embed cybersecurity within information systems instead of treating it as an afterthought issue.
Secure by design is common practice especially in software development endeavors. And it focuses on identifying security threats by vulnerability management, threat modeling, misuse cases, and vulnerability research programs.