title: Password Protecting an Excel file in C#
body: <p>Does anyone know the syntax for this?  I've been looking everywhere and all I can find is C++ code for this.  I'm trying to password protect an excel file programatically using the System.IO.Packaging namespace.  </p>
  
  <p>Any ideas?</p>
  
  <p>Additional notes:</p>
  
  <p>I'm NOT using the Excel interop--but instead the System.IO.Packaging namespace to encrypt and password protect the excel file.  </p>