This was an application lecture that followed the basics of networking. It definitely felt like it was more in-depth than before. In particular, thanks to the explanation of difficult content with easy examples, I was able to understand it much better than when I studied alone in the past. It was a bit difficult to follow the part where the last lecture was explained all at once, but I think it wasn't a big flaw because I could listen to it multiple times. And personally, when I listened to the SSL and PKI lectures first and then this lecture, I felt like I could understand the content in the latter half more smoothly. Of course, it's not that you have to listen to that lecture first, but if you listen to both, it would be okay to listen to them in that order. Thank you for the great lecture!