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

Keys in Web Crypto

Using the Web Crypto APIs, cryptographic keys are stored inside CryptoKey objects, which are used for both symmetric and asymmetric (private or public) keys. There are additional methods that allow us to generate, derive, import, and export keys that are stored in CryptoKey objects.

The CryptoKey object

All cryptographic keys that are used with Web Crypto APIs are contained in CryptoKey objects, which also determine what operations are possible with the keys and whether they're extractable.

In particular, a CryptoKey object contains the following properties, which are all read-only:

  • type is a string that indicates the type of the key. Its possible values are 'public' and 'private' for each part of an asymmetric key, and 'secret' for symmetric keys.
  • algorithm is an object that contains information about the algorithm the key can be used for, as well as extra parameters. We'll learn more about these...