Explain what do CIA $($i$.$e$.,$ confidentiality, integrity, availability$)$ mean in the smart home scenario. $(6$ points$)$ b$.$ Figure $2$ shows the whole process when the homeowner controls the home devices $($e$.$g$.,$ turn on the air$-$conditioner and set the mode as $$cool$$ and the temperature as $26$ degrees Celsius$)$ remotely. All the messages are transmitted unprotected thus confidentiality and integrity are both in danger. Assume the server is trusted. Describe your security design to achieve confidentiality and integrity. $(14$ points$)$