With your Excel file open, click the File tab on the Menu Bar.
Select the Info tab. Click on Protect Document, and then select Encrypt with Password.
In the Encrypt Document box type a password and click OK.
In the Confirm Password dialog re-enter the password and click OK.
Keep in mind that if you forget the password you will lose access to that document.
This only protects a single target document. Each Excel document you want to protect with a password must be done individually, and you can check on whether or not a document is protected in the Info tab.
The yellow box indicates that your document is now protected, and everyone will need a password to access the document. Click [Save] to save your document.
If you need to decrypt it, just repeat the steps above. When you get to the Encrypt Document box where you entered your password, simply delete the password.
Don't forget to [Save] to save your changes.
If you are having difficulty or you have unanswered questions, please contact the Help Desk through the ITS Service Catalog or call (518) 388-6400.