The first computer system later receives {HEAD ~ an encrypted response} from {TAIL ~ the second computer system} and processes the encrypted response to determine whether the second computer system is authorized to access the software 
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The first computer system later receives { HEAD ~ an encrypted response } from { TAIL ~ the second computer system } and processes the encrypted response to determine whether the second computer system is authorized to access the software
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH