Protect multiple worksheets with a stored password. Make worksheets very hidden using the Protect Sheets macro.
Excel 2010 has the inbuilt option to password protect Excel sheets and workbooks and also to hide them. But then, these features are basic in nature and does not offer full protection. Protect Sheets is a simple and freeware add-in for Excel which allows you to password protect work sheets and also to hide them so that people cannot view it unless they know the password for unlocking. The add-in once installed, works from the context menu of the Excel sheets.