Free online courseComputer systems security

Course Description

Modern software lives under constant pressure from attackers, mistakes, and unexpected interactions between components. This free online course in Cyber Security helps you build a practical, systems-first understanding of how security fails and how to design software that holds up in the real world. You will learn to think in threat models, reason about what an attacker can and cannot do, and connect those assumptions to concrete technical decisions.

The course focuses on security at the level where vulnerabilities become impactful: memory safety, operating system boundaries, and application isolation. You will explore why low-level implementation choices matter, how control-flow hijacking and buffer overflows happen, and what defenses try to prevent or contain. From there, you will see how ideas like privilege separation, capabilities, and sandboxing reduce risk by limiting what code can access, even after a compromise. Rather than treating security as a checklist, the course trains you to treat it as architecture plus enforcement.

Security also depends on the platform around your software, especially the browser and the network. You will examine the web security model, common web application weaknesses, and why certain design constraints exist in the first place. On the network side, you will connect historical protocol decisions to today’s attack surface, then build intuition for how authentication and encrypted transport work in practice, including protocols such as Kerberos and the role of SSL and HTTPS in defending against interception and tampering.

The course goes beyond classic topics to cover areas that frequently surprise developers and analysts: symbolic execution for finding bugs systematically, side-channel attacks that leak information without breaking encryption, and privacy features like private browsing and anonymous communication. You will also look at security on mobile devices, how modern smartphone architectures isolate apps, and how data tracking can be observed and controlled. Finally, you will connect technical choices to real incentives through security economics, a crucial lens for anyone building or defending systems.

By the end, you should be able to analyze threats more clearly, spot common exploitation paths, and choose mitigations that match your environment. If you are preparing for a role in security engineering, secure software development, or cyber security analysis, this course offers a strong foundation you can apply immediately.