about this book
Because you’ve opened this book, we assume that you’re a software developer or are closely involved in building software systems that run in production and handle real users, real data, and real risks. You might work primarily with Java and the JVM, but the principles in this book apply equally if you use Kotlin, Scala, or any other modern platform. Security isn’t tied to a single language; it’s tied to how systems are designed, built, and operated.
As a developer, you already make security-related decisions every day, often without realizing it. How you store passwords, how services talk to one another, how keys and certificates are managed, how data is serialized, logged, or cached—all these choices have security implications. Yet many security concepts are taught at a highly theoretical level or from the perspective of attackers, leaving developers unsure how to apply them in real systems.
This book takes a different approach. It focuses on security from a developer’s point of view. It explains how systems fail, how security mechanisms actually work, and how to use them correctly. The goal isn’t to turn you into a cryptographer or a security specialist; we want to give you enough understanding to make good decisions, recognize dangerous patterns, and ask the right questions.