Lesson 1 — How websites work
A browser sends requests to a server, which returns a response. HTML structures content, CSS styles it, and JavaScript adds interactivity. Server-side code and databases often handle accounts and stored data.
Lesson 2 — HTTP and HTTPS
HTTPS protects data in transit between a browser and a website using TLS. It helps protect confidentiality and integrity, but it doesn't automatically mean a website is trustworthy.
Lesson 3 — Authentication and sessions
Authentication checks identity; authorization determines what an authenticated user can do. Secure applications use careful session handling, least privilege, and safe account recovery.
Lesson 4 — Common vulnerability categories
Examples include broken access control, injection flaws, and security misconfiguration. Study these in deliberately vulnerable training applications or labs where testing is explicitly permitted.
Lesson 5 — Secure development
Validate inputs, encode output appropriately, use parameterized database queries, keep dependencies updated, and avoid exposing secrets. Consult the OWASP Top 10 and official framework guidance.