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)
1
Part 1 – Getting Started
4
Part 2 – Using Common Cryptographic Operations with Node.js
9
Part 3 – Cryptography in the Browser

Base64

The second common way of representing binary data is base64. As the name suggests, this uses an encoding with 64 different symbols, each one representing 6 bits of the underlying data.

Just like hex encoding splits the underlying data into groups of 4 bits and then maps them to a small subset of symbols (16 in total), base64 uses groups of 6 bits and a set of 64 symbols. There are multiple character sets and specifications for base64 encoding, but the most common ones are as follows:

  • The "Base64 standard encoding," as defined by RFC 4648 Section 4, uses the following 64 symbols:
    ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234 56789+/
  • The "Base64 URL encoding," as defined by RFC 4648 Section 5, uses the following 64 symbols:
    ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234 56789-_

The two encodings are very similar (and, unlike hex, these are case-sensitive), but they differ in the symbols used to encode the decimal numbers...