This app serves as an authenticator for Ciphermail encrypted PDF files. If Ciphermail cannot encrypt an email message to you, it puts the message in a PDF file. It sends you the PDF file with a key for your PDF Authenticator. With this key, PDF Authenticator generates the password with which you can open the encrypted PDF file. When you install the app, you need to personalize it with a personal master key that you obtain from the organization that sends you the email.