How to Password Protect an Office 2008 Document on a Mac
In Mac OS X Snow Leopard, along with the document-level sharing commands, you can add password protection to any Office 2008 document. To add password, protection, follow these steps with any document you created within Word, Excel, or PowerPoint:
Choose File→Save As.
The Save As dialog opens.
In the Save As dialog that appears, click Options.
This displays the Save Preferences pane.
Click the Show All toolbar button and Click Security to display the Preferences pane.
Office 2008 offers two types of document passwords.
Enter a password in the Password to Open field.
This password must be provided when opening the document.
If you like, you can enter another password in the Password to Modify field. This second password would then also be required to modify the document.
Both passwords are case sensitive.
Your changes are saved and you return to your document.
Think of the Protect Document dialog in Word, from which you can effectively write-protect certain elements, as an extra level of security in a multiuser environment. In this Office application, you can protect revision marks, comments, and sections of a document containing forms. A password can be added if desired. To display the Protect Document dialog, click Tools in any of the Office 2008 applications and choose Protect Document from the pop-up menu that appears.