Book Image

Essential Cryptography for JavaScript Developers

By : Alessandro Segala
Book Image

Essential Cryptography for JavaScript Developers

By: Alessandro Segala

Overview of this book

If you’re a software developer, this book will give you an introduction to cryptography, helping you understand how to make the most of it for your applications. The book contains extensive code samples in JavaScript, both for Node.js and for frontend apps running in a web browser, although the core concepts can be used by developers working with any programming language and framework. With a purely hands-on approach that is focused on sharing actionable knowledge, you’ll learn about the common categories of cryptographic operations that you can leverage in all apps you’re developing, including hashing, encryption with symmetric, asymmetric and hybrid ciphers, and digital signatures. You’ll learn when to use these operations and how to choose and implement the most popular algorithms to perform them, including SHA-2, Argon2, AES, ChaCha20-Poly1305, RSA, and Elliptic Curve Cryptography. Later, you’ll learn how to deal with password and key management. All code in this book is written in JavaScript and designed to run in Node.js or as part of frontend apps for web browsers. By the end of this book, you'll be able to build solutions that leverage cryptography to protect user privacy, offer better security against an expanding and more complex threat landscape, help meet data protection requirements, and unlock new opportunities.
Table of Contents (13 chapters)
Part 1 – Getting Started
Part 2 – Using Common Cryptographic Operations with Node.js
Part 3 – Cryptography in the Browser

Encoding and representing binary data

When using cryptography, including hashes, signatures, and encrypted messages, we commonly have to deal with binary data. As every developer has experienced while working with binary data or files, they cannot easily be printed on screen or copied and pasted into other fields, so it's common to change their representation by encoding them into strings that only use human-readable characters.

Figure 2.1 – Looking at binary data on a terminal. Note how the terminal is trying to interpret every byte sequence as UTF-8 and frequently encounters invalid ones (replaced with the "" symbol)

In Node.js, binary data is generally stored in Buffer objects and can be represented in multiple ways, including some encodings that are guaranteed to be human-readable. Throughout this book, we'll frequently use two ways of representing binary data: hex (short for "hexadecimal", which uses base16) and base64...