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

Trust and certificates

In this and the previous chapters, we learned how public-key cryptography allows us to have secure communication with another person over an untrusted channel, and how, with digital signatures, we also get integrity, authentication, and non-repudiation. All those things are excellent; yet, before we end our dissertation around this topic, there's one last thing we need to cover.

The problem of trusting keys

Let's assume you need to send some confidential information to your friend Alex over the Internet, so you decide to build a solution that uses public-key cryptography. Before you can send Alex a message, you know you need to ask them for their public key. You decide that, for increased security, you want Alex to send you their public key in a message that is signed with their private key (that is, Alex's message contains their public key and a signature that can be verified with the very same public key). This will act as a guarantee that...