6. Consider the exchange between Alice and Bob shown in Figure 4 that Oscar can eavesdrop. After this exchange, Alice and Bob decide to use EkAB(N+1) as the session key for encrypting communications. How can Oscar decrypt this communication without breaking the encryption scheme? Hint: Assume that Oscar can masquerade as Bob to Alice the next time she tries to connect to Bob.

am Alice Alice* Bob KAB(N)