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

Symmetric and asymmetric encryption

There are two main kinds of ciphers (and, consequentially, of encryption): symmetric and asymmetric, and the difference lies in the kind of keys that are used.

Symmetric encryption is probably the most well-known of the two, and the one that consumers are more likely to be familiar with as well. With symmetric encryption, you encrypt data using a key, and then use the very same key to decrypt it again. In many cases, the key can be derived from a password or passphrase, as we'll see at the end of this chapter.

Conceptually, algorithms such as AES (one of the most popular and widely used symmetric ciphers) and ChaCha20-Poly1305 work this way.

If you wanted to share the encrypted message with another person, you'd need to provide the other party with both the ciphertext (the encrypted data) and the key. Like many people, even consumers have experienced, in this case, the challenge of sharing the encryption key securely. Having the...