by When you first set up your Mac, the only security measure that’s enforced is that you add a password to your user account. The Setup Assistant makes no mention of extra measures you might want to enable, even though several are built into OS X. The features we’re about to look at are defenses against local attacks, rather than protection against online attacks. The measures are particularly important if you work in an open environment, such as a library, an office, or a café, and if your Mac is stolen, because they help to keep your data under lock and key.
One thing that isn’t covered here is FileVault, which encrypts everything on your Mac so it’s unreadable to anyone who doesn’t have your password. It’s what you might call a nuclear option, though, and carries a risk: if you lose both your password and backup recovery key, which lets you reset your password, you’re forever locked out of your files. You can store your recovery key with Apple, but three questions must be answered precisely for access, so this also carries a risk. FileVault is extremely secure, but its seriousness means we don’t recommend it for everyone.
