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

The what, how, and why of digital signatures

When we covered hashing in Chapter 3, File and Password Hashing with Node.js, we mentioned that we were going to be leveraging hashing functions in virtually every part of this book, and as we're looking at the last class of operations – digital signatures – we're certainly staying true to our word once again. In a sense, we could even say that digital signatures are an extension of hashes!

Hashes and digital signatures

Let's start with an example: you are sending a message to your bank, asking them "Please wire $100 to Alice." You want to be sure that the message doesn't get corrupted in transit (the difference between "$100" and "$500" is just one flipped bit!), so you attach a hash of the message. As we saw in Chapter 3, File and Password Hashing with Node.js, one of the main purposes of hashes is to guarantee the integrity of a message: a change in even a single bit...