Dark Reading is marking its 20th anniversary by looking at how cybersecurity has evolved from perimeter-focused defenses in 2006 to today's complex, AI-driven security landscape. The shift was driven by major infrastructure changes including cloud computing, mobile devices, and the Internet of Things, which forced security teams to move beyond simple firewalls and antivirus software to address identity management, data protection, and an expanding attack surface. While the technology and tactics have transformed dramatically, analysts note that core security principles remain the same—organizations still need to protect infrastructure, update systems, and train employees on security best practices.