Add new use case for additional payment authentication (#667)

Author: kenchris

use-cases.html

@@ -153,6 +153,12 @@
       specification.
     </p>
   </section>
+  <section><h3>Verifying unusual purchase activities</h3>
+    <p>
+      NFC can be used to verify unusual purchase activities, by having the user
+      touch the the credit card for additional authentication.
+    </p>
+  </section>
   <section><h3>Scenarios along side payment</h3>
     <p>
       Payment using NFC should be handled at a platform level due to security