Here are a few very simple steps you can take to enhance your Mac's security - not exactly the U.S. Government's Advanced Encryption Standard (AES) algorithm, but enough to thwart many end-users.
Create a guest user account
Occasionally, someone will ask me, "May I quickly check my email on your computer? Just real quick..." (often these are Windows users who need an excuse to play with the MacBook Pro). "Sure," I say, but before I hand over the reigns, I switch to my guest user account. Here's how you can create one.
- Click System Preferences, then Accounts
- Click the small "+" icon at the bottom of the window
- In the sheet that appears, set up your guest account. I got fancy and named mine "guest," with a password of "guestpw," but you can choose whatever you like.
- De-select "Allow user to administer this computer."
Create a hidden folder
Mac OS X automatically hides a folder that begins with a period. We can use this to our advantage and create a secret folder. However, it's not as easy as creating a folder in the Finder and naming it ".MyPrivateStuff." But it's not difficult, either.
- Open Terminal. By default, you're in your Home directory
- Create a new folder with a "." as the first character using the "mkdir" command, like this: mkdir .MyPrivateStuff
- Hit return. You're done!
One caveat: The Finder "remembers" the last folder you visited with this method, so be sure to "Go to..." a benign folder before you walk away.
Combine the two tips
If you really want to get fancy, combine the two tips: Create a new user account that does nothing but store your secret folder(s).
Again, this isn't military-grade security, but simple techniques that you can use as an extra layer of protection for some of your stuff. Good luck.