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