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

Chapter 5: Using Asymmetric and Hybrid Encryption in Node.js

In the previous chapter, Chapter 4, Symmetric Encryption in Node.js, we looked at how to protect the confidentiality of data by encrypting it using symmetric ciphers. Algorithms like the ones we used (AES and ChaCha20-Poly1305) are highly secure and fast, but they use a single key (in this case, a shared key) for both encryption and decryption. Consequently, to send an encrypted message to another person, both parties need to know the shared key too: safely transmitting that over an insecure channel (such as the internet) can become a problem.

As we briefly mentioned in the previous chapter, for these situations, it's often convenient to leverage a different class of cryptographic operations: asymmetric cryptography, also called public-key cryptography, since it uses two kinds of keys – a public key and a private key. RSA is one of the most popular and widely adopted algorithms for public-key encryption and...