Introduction

When I buy a computer book, I’m impatient. I want to get to the part of the book that tells me everything I need to get my stuff done. For this book, the important information is how to encrypt, decrypt, and digitally sign your data. That’s why the first page explains how to encrypt a file and how to verify a digital signature: Actionable information on every page is my motto.

There is much you should know about how to use encryption safely and securely, but it’s not easy to present all that information comprehensively and exhaustively but also accessibly (that is, “won’t put the reader to sleep by page 17”).

I began writing this book using the industry standard for computer books: start with the history of encryption, followed by a history of encryption software, then a comprehensive list of all current encryption software and exhaustive installation instructions on all platforms, and then the systematic death march defining and describing every step of every command and option of every program.

That was so boring that I couldn’t write for more than 20 minutes at a time before nodding off, let alone read it. Rather than attempting yet another catalog of mostly useless and mind-numbing technical trivia, I decided it would be more interesting (for all of us) to tell a story about how someone learns to do encryption.

Thus, what you are reading is a work of fiction: the characters and situations are made up, intended to give a human face to how encryption works and is used. The stuff about Bob and Sam, those things are made up--but what those people do with their computers is all real and true.

I could have included more introductory material, explained more about why open source software is preferable for security functions, why the command line beats GUI interfaces for learning about encryption, even how to use the command line. I have included notes to help you get started working along with the text, but most of what you need is revealed as the story moves forward. All in good time and (hopefully) never so much as to become boring.

If you just want the exhaustive set of facts and instructions, without context, pick a Gnu Privacy Guard tutorial¹ and have at it. If you want to understand and use encryption in the real world, read on and enjoy!