Hi and welcome. Teoh lesson 2.3. And this lesson, we're gonna talk about the network layer everything. In the last couple of lessons, we've been talking about the perimeter, which is that boundary between our internal devices and that external entity. Now, we're gonna move a little bit more inward on that layered approach. We're gonna talk about the network layer, which is
all of that backbone infrastructure, the routers and switches that connect
us to the outside world. As as well as connect devices together internally.
Now, within the network layer, we're gonna talk about a few different components. One is encryption we're gonna talk about We touched on encryption before a little bit when we talked about VP ends. But in this lesson, we're gonna go into how encryption works and dive in a little bit deeper on encryption itself.
We're gonna talk about Web proxies. What practice? Their basically just those devices that help us control how we interact, how our organization interacts with the Internet and with the outside web,
we're gonna talk about knack, which is network access control. And that's all about how we how we allow devices onto our network and what types of devices we allow onto our network,
and then we'll get into a little bit about wireless security towards the end of the lesson towards the end of the module,
we'll start with encryption
encryption, and it's in its basic form. Before we start to actually talk about functionality. Let's talk about some definitions because we're gonna use these over and over again.
When we say the word algorithm, we're referring to a mathematical formula used for encrypting. It's ah, it's just actually a formula A plus B equals C.
We talk about the word key. We're talking about a secret variable. It's something that secret. It's a variable that's used within that encryption algorithm. So if the algorithm is X plus one equals three than X is our key. It's what's unknown. It's what secrets what we have to solve for
We use the term cipher text. We're talking about the data that's actually been encrypted once the data is encrypted and we transmitted across the wire and an encrypted format. That's what we refer to sometimes a cipher text.
Symmetric encryption is encryption where both sides are using the same key, so that same secret or variable is in is hard coded or is known by both sides of the equation, whereas asymmetric encryption is where each party on each side uses a different key.
And then finally, public key Encryption is a nen crip shin method of mechanism that uses both asymmetric and symmetric encryption. We're gonna go. We're going to show you that towards the end of this lesson.
All right, let's talk about how encryption works.
In its most basic form, encryption is just creating a secret. It's just scrambling data in a way that others who don't know the secret can't read it.
So let's say we've got this computer over here on the left that wants to communicate with computer on the right
and what it actually wants to communicate is a password. In this case, we've got a password in clear text in our password is not on my watch.
The computer on the left is going to send that password through an encryption process, and that process is simply taking the data, which is the password, and applying it to an algorithm. And the output of that is gonna be our cipher text. And this cipher Texas. Nothing but jumbled up data. It's just random characters that if we transmit that over the wire
and someone happens to see that or intercept that, they're not gonna have any idea what that means, because it's just
gobbledygook. It doesn't mean anything.
Peter on the right is gonna receive that cipher text. It's gonna run it through a decryption process, which is simply applying it to that algorithm again.
And the output is gonna be the clear texts. And now the computer on the right. Kenly read the actual clear text.
That's all. Encryption is at its highest, highest level. That's all it's really doing. It's very complicated, the mechanisms that do that, but at its highest level, that's what it iss.
let's get into a little bit more details about the keys and the algorithms first off keys, as I said, our mathematical formulas used in the encryption and decryption process. But keys or not, I'm sorry. Algorithms air not secret algorithms are actually public. There's plenty of them out there. There's a handful of them that are stronger than others.
Um, they're all publicly available. They're not
any secrets at all. The formulas themselves are not secrets.
What our secrets are the keys, and those are the things that we need to keep. Keep quiet, keep a secret and protect. Because if you know the algorithm because it's public and you acquire the key, then you can solve the equation and you can read the data.
Good algorithms use a combination of both keys and the data itself to populate parts of the formula to make them more complex. So if we're starting, we want to encrypt some data. And we have We actually have two secrets. When we start, we have the key, which we know, and that's our secret. We also have the data.
If we haven't transmitted that data yet,
that data is secret as well. We can use that as part of our algorithm.