title: Excel File Password Protection with Open XML SDK
body: <p>I am using Open XML SDK for creating excel files. </p>
  
  <p>I want to protect them with a password.</p>
  
  <p>Do you know anyway to protect excel file with a password by using Open XML SDK?</p>
  
  <p>I know "com" object way to protect them however, it is not suitable for my application. I need to protect file by using Open XML SDK or another way.</p>