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