###### tags: `CDA`
# Reading Responses 1

## Sep 17 Tue - How the Web works

HTTP was like a language that websites use to communicate with clients. Some websites like banking websites need to use more advanced certificates in order to communicate securely with customers. There are a lot of protocols like Transmission Control Protocol and Internet Protocol and Hypertext Transfer Protocol that regulate web communication and data interactions. While I took the internet for granted, it surprises me that there are many rules and regulations in place to prevent snoopers and hackers from stealing data. For instance, many sites use HTTPS encryption with public key encryption or symmetric key encryption. There is a common exchange method called “Diffie-Hellman” exchange that allows a client and server to communicate in secret, even with a packet being public. In addition, websites are made from many files, such as HTML and CSS files.
I had previously heard of terms like “IP address”, but I never knew what the term IP stood for. It was interesting to me how web servers were actually hosted on computers rather than just some online entity, because I have created websites myself without having to worry about hosting servers on a computer. However, I have a friend who hosts a chess website called lichess.org, and he always has to worry about server costs. I saw a spreadsheet with the total server costs of hosting lichess.org and I was surprised at how expensive it was to host chess servers for chess players, as well as how expensive encryption was.
In a public chat room, I had a friend that created scripts using public key encryption. The group chat would fill up with encrypted messages that appeared as gibberish spam, but my friend would be able to communicate with other members of the group chat using private keys.
It was fascinating to me how large prime numbers are used in encryption, because it is cool how prime factorizations are easy to verify but hard to find. This relates to the P vs NP Millennium problem, which I attempted using Sudoku puzzles. This Millenium Problem asks if a solution is easy to verify, is it also easy to find? I believe that this is not the case, because I have attempted many math problems that are easy to check but hard to solve.