The concept of “protection” gets a lot of attention in the Excel newsgroups and forums. It seems that many users want to learn how to protect their workbooks from being copied or modified. Excel has several protection-related features, and those features are covered in this chapter.
Excel’s protection-related features fall into three categories:
Worksheet protection: Protecting a worksheet from being modified, or restricting the modifications to certain users.
Workbook protection: Protecting a workbook from having sheets inserted or deleted, and also requiring the use of password in order to open the workbook.
VB protection: Using a password to prevent others from viewing or modifying your VBA code.
Before I discuss these features, you should understand the notion of security. Using a password to protect some aspect of your work doesn’t guarantee that it’s secure. Password-cracking utilities (and some simple tricks) have been around for a long time. Using passwords work in the vast majority of cases, but if someone is truly intent on getting to your data, he or she can usually find a way. If absolute security is critical, perhaps Excel isn’t the proper tool.