Microsoft has introduced Office 2013 Preview, the next generation of Microsoft Office product. Excel 2013 ships as a part of Office 2013. The new Microsoft Excel 2013 is totally redesigned and reimagined with a Windows 8 and Metro Style app interface.Today we will learn how to protect your Worksheet from unauthorized access. In Excel 2013 Microsoft has provided a variety of ways to protect an Excel sheet. You can protect your worksheet by applying attributes from the options. The controls that protect your workbook are as follows:Mark as Final: When you mark your Excel sheet as Final this means it is a final version of the Excel sheet and the user cannot make any changes.Encrypt with Password: To open an Excel sheet the user requires a password.Protect current sheet: This controls specify the type of authentication that you want to provide to the other user.Protect Workbook structure: This controls protect your workbook from changes of the structure of the workbook. Such as the user cannot add an extra sheet to the workbook.Restrict Access: This control will also leads your workbook access from the other user and will grant persmissions related to edit, copy, and print etc.Digital singnature: This will ensure the intergrity of the workbook by adding an invisible digital singnature security to workbook.To access this feature follow the following steps:Step 1: Open the Excel workbook you want to protect.Step 2: Go to the File menu and select the Info option from the left-side panel.Step 3: Select the Protect workbook option from the right side.When you click on Protect workbook, you will see the various types of options to protect an Excel workbook as I described earlier.