Yeah? Different symmetric cipher key.

But here we're just going to focus on symmetric cipher where both sides use the same key.

Symmetric Point

Conical Symmetric

It's symmetric.

So for example, when you encrypt email messages, it's very common that every single email is encrypted using a different symmetric key.

It's symmetric around the vertex.

Well, actually, this is symmetric.

Do you enjoy looking non symmetric?

That these two triangles are symmetric

These two focal lengths are symmetric.

It's kind of perfectly symmetric in every way.

The ellipse is symmetric around the y axis.

As we go from the positive side these are actually symmetric, although I didn't draw it that symmetric it also approaches infinity.

Now the reason we say that these are symmetric ciphers is that both the encrypter and decrypter actually use the same key K. As we'll see later in the course, there are ciphers where the encrypter uses one key and the decrypter uses a different key.

Since this trapezoid is perfectly symmetric, since it's isoceles.

And actually, we see that this matrix is symmetric.

And they're symmetric around the center of the ellipse.

Because these two points are symmetric around the origin.

And it's symmetric, just as you would expect it, right?

Look how big it is. Look how symmetric it is.

So in a symmetric encryption system, basically, the two parties,

Because both sides of these trapezoids are going to be symmetric.

And it's symmetric around the line x is equal to 0.

It looks like oh let me try to draw this symmetric.

Up until the 1970's, cryptography had been based on symmetric keys.

Either one, those are symmetric statements. They mean the exact same thing.

And an interesting thing here is that this is all symmetric, right?

And so we could actually say that since these two triangles are symmetric.

Also, those super symmetric particles are very strong candidates for the dark matter.

And actually, these are symmetric around the line, y is equal to x.

Now, the building block for securing traffic is what's called symmetric encryption systems.

A circle, for example, is symmetric under rotations about the center of the circle.

Now we look at it from Bill's point of view, and it's completely symmetric.

looks like, hopefully. It should be symmetric... Let me redraw it, because that's kinda ugly.

A physicist looks for larger, more symmetric patterns that include the established pattern as a subset.

And we're gonna talk, in the first half of the course extensively about symmetric encryption systems.

So one thing to realize is that these two focus points are symmetric around the origin.

Maybe wrap it into a hexagon with a nice symmetric sort of cycle to the flappy parts.

Now, we said that we have these two foci that are symmetric around the center of the ellipse.

You know what it means. A circle, for example, is symmetric under rotations about the center of the circle.

Now, if this is g and this is h, we also know that this is g because everything's symmetric.

We gotta get that key quick. Yup, yup. Key, key.

While machines in a cluster do not have to be symmetric, load balancing is more difficult if they are not.

If one can change the identities of the players without changing the payoff to the strategies, then a game is symmetric.