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


In this chapter, we learned about encrypting data with a symmetric cipher, starting with AES. After learning about how to use AES, including how to choose the size of the key, how to select a mode of operation (especially CBC and GCM), and how to generate an IV, we saw code samples for encrypting and decrypting data and streams with AES using Node.js. We then learned about ChaCha20-Poly1305, another symmetric stream cipher that's similar to AES-GCM.

Next, we explained how to derive encryption keys from a passphrase, stretching lower-entropy strings into safer keys for usage with symmetric ciphers. We saw examples of doing that with Argon2.

Finally, we learned how keys can be wrapped (encrypted), and why doing so can help solve real-world problems when applications use keys derived from passphrases to encrypt and decrypt users' data.

The next chapter will be the first one that covers the other kind of ciphers – asymmetric ones. We'll learn how...