To allow only authorized users to view or modify your data, you can help secure your entire workbook file with a password. 1. On the File menu, click Save As 2. On the Tools menu, click General Options. 3. Do either or both of the following:
    • If you want users to enter a password before they can view the workbook, type a password in the Password to open box, and then click OK.
    • If you want users to enter a password before they can save changes to the workbook, type a password in the Password to modify box.
 Note   Unlike passwords you specify in the Password to open box, passwords you specify in the Password to modify box are not encrypted. These passwords are only meant to give specific users permission to modify workbook data. For optimal password security,...