Laptops, tablets, cell phones, and smart watches: computers are inescapable. But even more are invisible, like those in appliances, cars, medical equipment, transportation systems, power grids, and weapons. We never see the myriad computers that quietly collect, share, and sometimes leak vast amounts of personal data about us, and often don’t consider the extent to which governments and companies increasingly monitor what we do. In Understanding the Digital World, Brian W. Kernighan explains, in clear terms, not only how computers and programming work, but also how computers influence our daily lives. Recently, Kernighan answered some questions about his new book.
Who is this book for? What kind of people are most likely to be interested?
BK: It’s a cliché, but it really is aimed at the proverbial “educated layman.” Everyone uses computers and phones for managing their lives and communicating with other people. So the book is for them. I do think that people who have some technical background will enjoy it, but will also find that it will help their less technical friends and family understand.
What’s the basic message of the book?
BK: Computers—laptops, desktops, tablets, phones, gadgets—are all around us. The Internet lets our computers communicate with us and with other computers all over the world. And there are billions of computers in infrastructure that we rely on without even realizing its existence. Computers and communications systems have changed our lives dramatically in the past couple of decades, and will continue to do so. So anyone who hopes to be at least somewhat informed ought to understand the basics of how such things work. One major concern has been the enormous increase in surveillance and a corresponding reduction in our personal privacy. We are under continuous monitoring by government agencies like the NSA in the United States and similar ones in other countries. At the same time, commercial interests track everything we do online and with our phones. Some of this is acceptable, but in my opinion, it’s gone way too far. It’s vital that we understand better what is being done and how to reduce the tracking and spying. The more we understand about how these systems work, the more we can defend ourselves, while still taking advantage of the many benefits they provide. For example, it’s quite possible to explore interesting and useful web sites without being continuously tracked. You don’t have to reveal everything about yourself to social networks. But you have to know something about how to set up some defenses. More generally, I’m trying to help the reader to reach a better than superficial understanding of how computers work, what software is and how it’s created, and how the Internet and the Web operate. Going just a little deeper into these is totally within the grasp of anyone. The more you know, the better off you will be; knowing even a little about these topics will put you ahead of the large majority of people, and will protect you from any number of foolish behaviors.
Can you give us an example of how to defend ourselves against tracking by web sites?
BK: Whenever you visit a web site, a record is made of your visit, often by dozens of systems that are collecting information that can be used for targeted advertising. It’s easy to reduce this kind of tracking by turning off third-party cookies and by installing some ad-blocking software. You can still use the primary site, but you don’t give away much if anything to the trackers, so the spread of information about you is more limited.
If I don’t care if companies know what sites I visit, why should I be worried?
BK: “I’ve got nothing to hide,” spoken by an individual, or “If you have nothing to hide, you have nothing to fear,” offered by a government, are pernicious ideas. They frame the discussion in such a way as to concede the point at the beginning. Of course you have nothing to hide. If that’s true, would you mind showing me your tax returns? How did you vote in the last election? What’s your salary? Could I have your social security number? Could you tell me who you’ve called in the past year? Of course not—most of your life is no one else’s business.
What’s the one thing that you would advise everyone to do right now to improve their online privacy and security?
BK: Just one thing? Learn more about how your computer and your phone work, how the Internet works, and how to use all of them wisely. But I would add some specific recommendations, all of which are easy and worthwhile. First, in your browser, install defensive extensions like like AdBlock and Ghostery, and turn off third-party cookies. This will take you less than ten minutes and will cut your exposure by at least a factor of ten. Second, make sure that your computer is backed up all the time; this protects you against hardware failure and your own mistakes (both of which are not uncommon), and also against ransomware (though that is much less a risk if you are alert and have turned on your defenses). Third, use different passwords for different sites; that way, if one account is compromised, others will not be. And don’t use your Facebook or Google account to log in to other sites; that increases your vulnerability and gives away information about you for minor convenience. Finally, be very wary about clicking on links in email that have even the faintest hint of something wrong. Phishing attacks are one of the most common ways that accounts are compromised and identities stolen.
Brian W. Kernighan is a professor in the Department of Computer Science at Princeton University. He is the coauthor of ten other books, including the computing classic The C Programming Language (Prentice Hall). He is the author of Understanding the Digital World: What You Need to Know about Computers, the Internet, Privacy, and Security.