1) R broadcasts message Req and T sends its IDS to R.
2) R computes Gn ID and sends it to T , however,
A blocks this message flow and hence, the transaction
between R and T drops.
3) A now broadcasts Req and T sends its IDS to A.
4) A sends the recorded message Gn ID to T .
5) T computes KnGn+1 and K0n
Gn+2. T then sends
these two messages to A, and updates IDS = F(IDS