• Depending on whether you use Windows, Mac, or Linux, there is a variety of built-in or free software for encrypting your hard drive. The Electronic Freedom Foundation offers a great tutorial on the subject, so visit its website and set aside an evening when your computer can finish the encryption uninterrupted overnight.
• Encryption only works if you have a strong password. That means long, random, and hard to guess. Experts recommend choosing a long “passphrase,” consisting of five or more words strung together, which is easier to memorize.
• Switch to HTTPS and your computer will communicate with websites using encryption, meaning third parties can’t decipher your data even if they’re eavesdropping. Gmail does this automatically, and you can enable the feature in your account settings on Facebook, Twitter, and a number of other sites.
• Turn on your firewall to help block unauthorized access to your computer. Do this in the Security menu in Control Panel, if you’re using Windows, or in System Preferences, if you’re using Mac.
Matthieu Aikins is a freelance journalist who writes for Harper’s, The Atlantic, GQ, and other magazines