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