For a simple way to password-protect a PDF on your Mac, use the built-in Preview application. Open the PDF (or other file) in Preview, then choose File> Export.
In the dialog box that appears, click on Encrypt, type in your desired password, and click Save.
If you don’t change the name or location of the file, the existing one will be overwritten with your password-protected version.
Jay Nelson is the editorial director of PlanetQuark.com, and the editor and publisher of Design Tools Monthly. He’s also the author of the QuarkXPress 8 and QuarkXPress 7 training titles at Lynda.com, as well as the training videos Quark includes in the box with QuarkXPress 7 . In addition, Jay writes regularly for Macworld and Photoshop User magazines and speaks at industry events.