Security Tutorial

In the previous tutorial, you learned how to authenticate users — verifying who they are. But authentication alone is not enough. You also need authorization — controlling what they can do. Authentication answers: “Who are you?” Authorization answers: “What are you allowed to do?” Authentication vs Authorization Authentication Authorization Question Who are you? What can you do? When During login After login, on every request Method Password, JWT, biometrics Roles, permissions, policies Example “You are user Alex” “Alex can read posts but not delete them” A common mistake is checking authentication but skipping authorization. The user is logged in, so the app trusts them completely. This leads to Broken Access Control — the #1 risk in the OWASP Top 10. ...

In the previous tutorial, you learned the OWASP Top 10 security risks. Authentication failures (A07) are one of the most common. In this article, you will learn how to store passwords safely and implement token-based authentication with JWT. Why Passwords Are Still the #1 Target Despite all the advances in security, passwords remain the most common attack vector. Here is why: People reuse passwords across websites Weak passwords are easy to guess with brute force Many applications still store passwords incorrectly The LinkedIn breach in 2012 exposed 117 million passwords hashed with unsalted SHA-1. Attackers cracked most of them within days. The Adobe breach in 2013 exposed 153 million passwords encrypted (not hashed) with 3DES — all using the same key. ...

Most security breaches happen because of simple mistakes. A missing access check. An unvalidated input. A hardcoded password. In 2024, the average cost of a data breach was $4.88 million (IBM). Studies consistently show that human error is a major factor in security incidents. The good news? You do not need to be a security expert to write secure code. You just need to know what to watch for. This is the first article in the Security for Developers series. We will start with the OWASP Top 10 — the most widely used list of web security risks in the world. ...