Key Points:

We have lots of reasons to keep secrets

Modern encryption is made up of many different tools

Key points:

Ciphers take a plaintext message and turn it into ciphertext

They can be reversed to get the plaintext back

They require a secret key to work

Basic ciphers are symmetric, they use the same key to encrypt and decrypt

Problems:

Swapping the secret key safely

Key points:

Two users can create a secret that no one else knows

They can do this in public even if others are listening

Problems:

They can't tell that they are talking to the right person

Key points:

Now users can send messages that only the intended recipient can read.

They can use this system to prove that they are who they say they are.

Problems:

This is SLOW. Not good for lots of data

How do you know the public key you have is actually from the right person?

Key points:

Not the same as encryption but very useful

Great for checking to see if your data is undamaged

Big (but simple) concept:

Key points:

Almost all symmetric encryption is done with AES. It is so fast, common and reliable that it's even built into most hardware.

Key points:

SHA - 256 is good.

Key point:

It's not really encryption but it's in the exam.

Rolling codes and AES (again!)

Key points:

Real communication uses all these things

Almost all online communication uses TLS