I dare say that this is a truly rare Spring Security course, both domestically and internationally. I am listening to all three lectures by instructor Jeong Su-won, and I am amazed by the unique teaching pattern of instructor Jeong Su-won, such as the lecture content, preparation of materials, digging into the internal structure through debugging, and analyzing the entire architecture. Wow, digging into security like this... I think developers who have developed security will also be amazed by this lecture. As you know, Spring Security has a large learning curve, so it is not easy for intermediate developers to deeply understand the internal structure and flow, but this lecture provides sufficient technical foundation knowledge for beginners to intermediate developers and above. It explains in detail and easily so that difficult security does not feel like being possessed by magic, by combining appropriate theories and appropriate practices. In particular, the part where the structure and flow of Spring Security are explained in detail through well-prepared PPT diagrams and diagrams, and this is proven through debugging with code, is the highlight of this lecture and seems to be the instructor's know-how. I am also learning one by one by keeping an eye on this method of progress. Before taking this lecture, I only knew how to follow security, but after taking this lecture, I was able to acquire the ability to freely expand and customize functions according to the situation as well as the basic functions of security such as API, filter structure, authentication/authorization internal flow, and dynamic authorization control method. I would like to evaluate this lecture as an incredible level. I think it provides quality and information that can be counted among the lectures on Inferun. In fact, since security lectures are not a technology that anyone can teach if they want to, I think this lecture is even more valuable. After listening to it all, I realized how difficult and hard it would have been if I had tried to acquire this much knowledge on my own. When I search for security on Google, I see that the instructor's lecture contents are searched a lot, so I am really grateful that you have lowered the barrier to entry by spreading the high barrier to entry security knowledge to many developers. There was a problem where the explanation content and the provided GitHub source were not partially synchronized during the lecture, but fortunately, the instructor organized the branch names of the sources that were mapped to the lecture in Excel, so it was much easier to follow. There were some differences between the lecture content and the actual practice, but there was no difficulty in understanding the overall content. Still, I hope that you will look into these small parts more carefully in the next lecture. Now, I am looking forward to and anticipating Instructor Jeong Su-won's next lecture. Through knowledge sharing by developers like you, our junior developers will experience minimal trial and error. I will sincerely support the instructor's knowledge sharing activities in the future. Thank you.