user: Rewrite the below text (which is a fragment of a longer script for the video). Fix grammar and other errors and make it sound more professional.

Networks and security, or how to connect the digital world. How can we exchange data quickly and efficiently. There are different types of networks.
A local area network (LAN) is for smaller, more local networks - home, business, school, etc.
A wide area network (WAN) covers larger areas such as cities and even allows computers in different countries to connect.
An intranet is a private enterprise network designed to support an organization's employees in communicating, collaborating, and performing their roles, usually to the exclusion of outside access.
We also have the well-known internet, which is the largest network connecting computers around the world.

But of course someone could try to intercept that communication. And we want to securely exchange data. We want to find vulnerabilities and defend against hackers.
This is why we have something like cryptography. It is a field of study that focuses on the encoding and decoding of info using special algorithms. So only the sender and receiver can know the content of the message.
There are many ways to protect your data, programs, devices and networks. Besides cryptography, we also use antivirus programs that can check if anything looks suspicious. A very popular trend is also the use of artificial intelligence to defend against hackers. But hackers can also use AI to attack. So it's a double-edged sword.

assistant: #Networks and Security, or How to Connect the Digital World

How can we exchange data quickly and efficiently? 
There are computer networks for this, and there are different types of networks for different needs:
A local area network, or LAN, is for small networks, like those used in homes, offices, and schools.
A wide area network, or WAN, works on the scale of cities, and sometimes even supports international connections.
An Intranet is a private network, usually run by enterprises to support private communication within the organization. An Intranet can support employees communicating, collaborating, and performing their roles, with minimal risk of exposing sensitive data outside of the network.
And of course there's the Internet, perhaps the most well known network of all. It supports global communication with open access to connect machines and people around the world.

A primary concern with any network is security. Secure and private communications face attempts to intercept the information on the network. Researchers are constantly trying to find and patch vulnerabilities that could be exploited by hackers.
Cryptography is a key part of the solution. Cryptography is a field of study focused on algorithms for encoding and decoding information. When done properly, this allows only the sender and intended receiver to read the content of a message.
There are many ways to protect your data, programs, devices, and networks. Aside from cryptography, antivirus software can check for suspicious activity. Artificial Intelligence, or AI, has also been employed to defend networks from hackers. But many of these same tools, including AI, can be used by hackers to find new exploits. It's a constant arms race for network security researchers.

user: Can you expand upon each paragraph?

assistant: #Networks and Security, or How to Connect the Digital World

Humans have an innate desire to communicate, it's how we've built communities and built the modern world. As technology expands, it's opened new methods of communication, leaving us constantly trying to answer the question, how can we exchange data more quickly, reliably, and efficiently? 

Computer networks have played a large part in recent history of filling this need for communication. There are different types of networks for different communication needs which will be described here:
A local area networks, or LANs, connect homes, offices, and schools in relatively small networks, typically up to a few hundred PCs.
A wide area network, or WAN (not to be confused with wireless area networks, which sometimes receive the same initialization), works on the scale of cities and beyond, sometimes supporting international connections.
An Intranet is a private network, usually run by enterprises to support private communication within the organization. An Intranet can support employees communicating, collaborating, and performing their roles, with minimal risk of exposing sensitive data outside of the network. Intranets can be accessed with physical connections to the enterprise network, wireless connections through routers connected to the physical network, or through a technology called VPN.
A virtual private network, or VPN, routes network traffic through a so-called "tunnel" connecting a trusted machine to a trusted network with an untrusted network in between them. In the enterprise application, this allows workers to connect to an Intranet as if they were local, even if they are remote and can not control all the network conditions of the connection.
There is also the Internet, perhaps the most well known network of all. It supports global communication with open access to connect machines and people around the world. It is built of multiple layers of network technology, developed by government and academic research programs over many years, with improvements being made all the time to improve the experience, reliability, and throughput of the network to enable an ever increasing amount and quality of communication.

A primary concern with all of these networks is security. Fundamentally, these networks exist for communication, and a great deal of that communication is intended to be private. Networks are attacked by people and agents seeking to reveal private information for a variety of purposes from profit, to national security, and various other motives. Researchers are constantly trying to find and patch vulnerabilities that could be exploited by hackers.
Cryptography is a key part of the solution. Cryptography is a field of study focused on algorithms for encoding and decoding information. When done properly, this allows only the sender and intended receiver to read the content of a message.
Public key cryptography relies on each party generating a long random number that would be hard for an adversary to guess, they can use this number to encode a message, they can also share a key that is 'public' in the sense that it does not allow for reading the encrypted communication even if is obtained by a hacker, but two parties with their own private keys can exchange public keys, and the combination allows messages encoded by one to be decoded and read by the other, but not by anyone with out one of the private keys. There are many encryption schemes, but as a whole, they are what allow reliable private echange of data over public or compromised networks. There are many ways to protect your data, programs, devices, and networks. Artificial Intelligence, or AI, is now being employed to defend networks from hackers. But many defensive tools, including AI, can also be used by adversaries to find new exploits. It's a constant arms race for network security researchers, that has led to consistent improvements in cryptography and network design.