Gets or sets the password to load an encrypted workbook. Use the WorkbookImportOptions.Password property instead.
A string value that specifies the password.
You can access this nested property as listed below:
|Library||Object Type||Path to Password|
|Office File API||DocumentOptions|
Use the WorkbookImportOptions.Password property instead. That property works for binary .xls as well as for OpenXml .xlsx files. For an example of use refer to the How to: Open and Save a Password Encrypted File article.