# File lib/prawn/security.rb, line 88
      def encrypt_document(options={})
        Prawn.verify_options [:user_password, :owner_password, :permissions],
          options
        @user_password = options.delete(:user_password) || ""

        @owner_password = options.delete(:owner_password) || @user_password
        if @owner_password == :random
          # Generate a completely ridiculous password
          @owner_password = (1..32).map{ rand(256) }.pack("c*")
        end

        self.permissions = options.delete(:permissions) || {}

        # Shove the necessary entries in the trailer.
        @trailer[:Encrypt] = encryption_dictionary
        @encrypted = true
      end