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

Hashing and key derivation

Hashing was the first operation we covered in this book, in Chapter 3, File and Password Hashing with Node.js. As you will recall, hashing functions can be used for a variety of purposes, including the following:

  • Calculating the checksum (or digest) of a document or file. For this specific scenario, we recommended the use of the SHA-2 family of hashes (including SHA-256, SHA-384, and SHA-512).
  • Hashing passwords before they're stored in a database. In this case, we recommended using algorithms in the Argon2 suite or scrypt.
  • Deriving symmetric encryption keys from low-entropy inputs such as passphrases, as we saw in Chapter 4, Symmetric Encryption in Node.js. For this scenario, we once again recommended using Argon2 or scrypt.

Support for calculating digests with SHA-2 is built into the Web Platform, and at the time of writing, it is one of the only two hashing algorithms that have been standardized and are available in all browsers...