Add more potential mitigations in security mechanisms (#533)

Author: beaufortfrancois

index.html

@@ -4246,6 +4246,16 @@ <h3>Parsing content</h3>
         The [[[PERMISSIONS]]] API is suggested to be used by UAs
         for implementing NFC related permissions.
       </p>
+      <p>
+        Implementations MAY use per-session/ephemeral permissions.
+      </p>
+    </section>
+    <section> <h3><dfn>Warning user during NFC operations</dfn></h3>
+      <p>
+        Implementations MAY show an overlay dialog whenever the NFC adapter is
+        being accessed by the web page (e.g. there is an ongoing scan) in order
+        to warn user.
+      </p>
     </section>
   </section>
   <section class="informative"> <h2>Security mechanisms for applications</h2>