1) R broadcasts message Req and T sends its IDS to R.
2) R computes Gn ID and sends it to T .
3) T computes KnGn+1 and K0n
Gn+2. Next, T sends
these two messages to R, however, A injects random
nx 2R f0; 1gl to the message K0nGn+2, (K0n
Gn+2
nx). Finally, T updates IDS = F(IDS Gn) and
Gn = Gn+1.