If you have to deal with complex workbooks, protected sheets, or need to speed up your Excel workflows, exploring the Security tools in Kutools for Excel is a smart move.
Kutools builds upon Excel's internal environment to deliver several distinct security mechanisms via the tab: kutools for excel password work
In older versions of Excel (such as Excel 97-2003 formats or XLS files), worksheet protection and "Password to Modify" restrictions were notoriously weak. They did not encrypt the actual data; they simply applied a simple hash flag that told Excel to restrict editing user interface elements. If you have to deal with complex workbooks,
Kutools for Excel offers a 30‑day free trial with full functionality. A license costs $49.00 as of the latest release, with free upgrades for two years from the purchase date. Kutools for Excel offers a 30‑day free trial
What (e.g., Excel 2016, Office 365) are you currently running?