[Teisha Nolen]

Although all the OWASP security principles are important, the one that stands out to me is Defense in Depth. It’s the idea that no single control is enough. Instead, we need multiple, overlapping layers of protection—firewalls, authentication, encryption, monitoring, and user education—all working together. This principle is critical as threats continue to evolve. If one layer fails or is bypassed, others are still in place to catch the breach. Each layer plays a role in reducing risk.
At my workplace, we implement several lines of defense. One practice that’s always fascinated me is our partnership with a team of ethical hackers who regularly test our systems for vulnerabilities. We also conduct ongoing employee training to help staff recognize how easily we could become access points if we’re not careful.
Defense in Depth isn’t just a best practice—it’s resilience in action. It reflects a mindset that anticipates failure and builds with redundancy, which is exactly what secure systems need to thrive.