Client checks the response NB+1. If the response is not correct, Client terminates the connection. Otherwise, the handshake is successful and the Client starts the conversation with the Host. If the handshake is done successfully Either Alice or Bob can send a message encrypted and authenticated by the key K. They type the message on their own terminal. The message is processed by their code (Host or Client) according to step 2 given above. The received message is printed on the screen if decryption is successful. Otherwise, an appropriate error message is displayed on the screen. To terminate the connection, either party should type "exit.