the external storage is polled by the second application for {HEAD ~ the presence} of {TAIL ~ an encrypted electronic message}, 
of
the external storage is polled by the second application for { HEAD ~ the presence } of { TAIL ~ an encrypted electronic message } ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH