Create a password for the files that you don't want others to open unless you give them the password, and choose an encryption type that's used to help protect information in your files. Then create a second password to help control who can make changes to the data in the files after the files are opened.
Find out how to help protect a worksheet so that data can only be entered or revised in certain areas, or hide a formula from view so that only the formula result is seen.
See what you can do to help protect your computer from the outside world by learning about computer viruses, macros, and digital certificates and signatures.
To learn more about this course, read the overview in the center of this page or the table of contents in the left column. Then click Next to start the first lesson.