However, {HEAD ~ the authentication device} or method may also be used to authenticate a user to the remote service, or indeed, mutually authenticate a remote service and {TAIL ~ a user} 
However , { HEAD ~ the authentication device } or method may also be used to authenticate a user to the remote service , or indeed , mutually authenticate a remote service and { TAIL ~ a user }
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL