title: Check if a Outlook Mail (*.msg) is Digitaly Signed or Encrypted
body: <p>I have a Web application that allows to upload Outlook Mails (*.msg) with File Upload.
  The customer want to forbid the store Mails that are Digitaly Signed or Encrypted.
  So after uploading the Mail I should someshow check the mail if it's Signed or Encrypted.</p>
  
  <p>If there a way to check that? Like a pattern in the Stream of the File? </p>