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

Binary data in the browser

In Chapter 2, Dealing with Binary and Random Data, we saw how, in Node.js, binary data is typically stored in Buffer objects and how those contain utilities to encode to, and decode from, strings too. Sadly, the Buffer API is one that, to this day, remains specific to Node.js, while the Web Platform opted for a different (more flexible, but possibly more complex) approach.

Buffers and typed arrays in the browser

In the JavaScript specifications supported by web browsers, binary data is stored inside buffers (which is not the same as Buffer objects in Node.js!) and is accessed through views such as typed arrays.

The ArrayBuffer object implements buffers as a chunk of fixed-length data. You can't access data inside an ArrayBuffer object directly, and there are only a few methods and properties in this object that you need to know about:

  • You can create a new ArrayBuffer object with the new ArrayBuffer(length)
constructor, where...