Encryption is enabled by the exchange of at least one key and {HEAD ~ the generation} of {TAIL ~ additional keys} by the access point and the mobile computing unit to make the communications secure 
Encryption is enabled by the exchange of at least one key and { HEAD ~ the generation } of { TAIL ~ additional keys } by the access point and the mobile computing unit to make the communications secure
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH