In operation, {HEAD ~ the authentication engine} receives a request having associated therewith {TAIL ~ a protect string} 
In operation , { HEAD ~ the authentication engine } receives a request having associated therewith { TAIL ~ a protect string }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL