You shouldn't need a Ph.D in Applied Cryptography to build a secure web application. Enter libsodium, which allows developers to develop fast, secure, and reliable applications without needing to know what a stream cipher even is.

After reading this brief electronic manual, you should...

Know what libsodium is, what features it has, and how to install it (both the library and the PHP extension from PECL).

Generally understand which cryptography tool to use for a specific scenario.

Be capable of writing production-quality code that uses libsodium.

Chapter 1 should explain what libsodium is, introduce some basic concepts, and guide you through installing libsodium and the PHP extension.

Chapter 2 aims to be a useful reference page for all the functions and constants exposed by libsodium.

Chapters 3 - 9 cover the various functions that libsodium offers, what their purpose is, and how to use them.

Chapter 10 contains "recipes": Example code that uses libsodium to satisfy a project requirement.