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

Calculating and verifying digital signatures with Node.js

In this section, we'll learn how to use Node.js to compute and verify digital signatures using RSA and ECC. Luckily for us, the Node.js built-in crypto module contains all the functions we need to do that.

Using RSA

To start, we're going to look at using RSA to calculate and verify digital signatures with Node.js by using crypto.sign and crypto.verify:

6.1: rsaSign and rsaVerify (part of signatures-rsa.js)

const crypto = require('crypto')
function rsaSign(privateKey, message) {
    return crypto.sign(
            key: privateKey,
            padding: crypto.constants.RSA_PKCS1_PSS_PADDING...