At the very least, losing your wallet to a thief is a major pain in the neck: you lose your cash and (possibly) some precious mementos, and you have to cancel your credit cards and replace your driver’s license. More seriously, the thief could steal your identity, using your personal information to make purchases, get loans, or cause you all kinds of grief by pretending to be you.
All that and more could also happen if your Mac’s data were to fall into the wrong hands.
Privacy software addresses concerns like these by making sure that any confidential information you keep on your computer or send across the Net can be seen only by you and the people you designate. In most cases, that means using some form of encryption.
Threats to computer privacy—and the software tools that address those threats—fall into two broad categories: threats from physical loss and threats from electronic snooping.
Physical Loss Computer theft is unfortunately quite common. Thieves are certainly interested in your Mac, either to keep or to sell. But anyone with a bit of curiosity and a few minutes could discover all kinds of useful things about you by examining your files—especially if your keychain is unlocked or has an easily guessable password.
A laptop is more likely to be stolen than a desktop, especially if it spends a lot of time outside your home or office. A Mac Pro in a locked room of an isolated house with a big guard dog is certainly less likely to be stolen than a MacBook Air you carry with you all the time as you walk around a big city.
Also, laptops are frequently simply lost—left on restaurant tables or at bus stops, forgotten at airport security checkpoints, or otherwise misplaced. Although an honest person might locate and return your lost computer, you might not be so lucky.
Even if your computer is right where it’s supposed to be, other people can still get to your personal information. Family members, friends, or coworkers, say—any of them could, in theory, snoop around on your hard disk. And if your Mac breaks down, any repair technician could potentially see your private data.
Electronic Snooping A criminal doesn’t need physical access to your Mac to do you wrong. He or she can snoop into your network traffic (unencrypted Wi-Fi connections are especially easy), looking for strings of characters that might be passwords, account numbers, and the like.
There’s no way to determine the exact likelihood of your network traffic being intercepted. But anecdotal evidence suggests that snooping is quite common. Whenever you use an unsecured wireless network—from an office, coffee shop, airport, or park bench—someone could be eavesdropping.
Snooping on wired Internet connections is harder but still possible. In theory, anyone who can tap into the network at any point between you and the servers you visit (for example, an employee of an ISP, a government agent, or someone else with physical access to one of the many routers your data passes through) could pick out your passwords, account numbers, and other private data.
Whether you’re talking about physical vulnerabilities or electronic ones, you do have the odds in your favor. Thieves, hackers, and spies have only so much time to do their work. They can’t attack all the computer users out there. But even if the odds are one in a million that you’ll be attacked in this way, you can make it just about impossible by using encryption and other software to protect your privacy.