Internet Notes

The internet started out as a program created by Bob Kahn used in the depart of defense, which eventually evolved into what we know today. The internet is all a physical system that moves information with wires, cables, and wifi.
There are three ways you can send info:

Method Pro Con
Electricity Cheap Signal loss
Light Really fast, no signal loss Expensive, hard to work with
Radio Totally mobile Short distance

IP Adresses and DNS

Each device has its own IP address, which traditionally has 32 bits inside. Currently, our world mostly uses ipv4, (the 32 bit one) but it can only have up to 4 billion unique addresses, so we're slowly moving over to ipv6. Ipv6 has 128 bits inside.
A DNS is a Domain Name System, and it takes the IP Address of a device and relates it to a specific name. There's also packets, which are pieces of info that is sent all over the internet. They can be controlled by routers, which transports them to somewhere. The Transmission Control Protocol will check that all packets have arrived and sign off on it.

Encryption and public keys

Encryption is the scrambling or changing a message to hide it. There's also decryption, which is unscrambling those messages.
One method of encryption is Asymmetric encryption: Using different keys for encrypting and decrypting.