Encrypting the data in a downloaded Gradebook helps protect the privacy of student grades. This tutorial shows how to do so using Excel from Office 2011 for Mac.
Open the downloaded file in Microsoft Excel.
Select Save As from the file menu.
Click on the Options... button.
Enter a password in the Password to Open field and click OK.
Re-enter the password to verify.
Next, click Save.
To delete files so that they cannot be recovered choose Finder then Secure Empty Trash.
This is recommended for the original downloaded gradebook file, as it contains sensitive student information.