Welcome back. I'm
going to go over the general outline of applied cryptography over
the next few lessons. I'll introduce you to a concept tree that fits
all the different ideas together and will
help us apply what we need for this course in terms
of applied cryptography. Now, the goal here is to give you enough of an understanding of applied cryptography
so that you have the ability to
differentiate between kinds of algorithms and know which kind of algorithm to
use in a given instance. We're going to basically do an overview so you
have the context. But what I'm not going to be
doing in these lessons is to present you the math and the theory behind
applied cryptography. You can get a really
excellent in-depth discussion if you read the very
excellent textbook called "Cryptography
Engineering: Design Principles and
Practical Applications" by Ferguson, Schneier, and Khono. So the basic outline of what
we're going to talk about today is outlined in general in this concept tree
that I've created. So this concept tree is
based on relating each of the concepts of applied
cryptography to one another. This is a subset of applied cryptography that we
want to use for this course. Now, applied
cryptography of course, is a very large topic, but we're only going to touch
upon a small subset of it. But nonetheless, the concepts that we're going to talk
about can be thought of as being related to one another as drawn here
in this concept tree. I'm showing you this tree
so that you can understand better where things fit together and how they fit
together conceptually. This concept tree is not based on the importance
of the concept, it's just how they fit together is what I'm
highlighting here. So with that said, first, we're going to go and start with looking at block ciphers, and then block
cipher modes of operation. Then we're going
to work our way up this part of the concept tree to symmetric key encryption. Next, we're going to talk about an introduction to the idea behind asymmetric cryptography, and then we're going to talk about public and private keys. Then we're going to see asymmetric cryptography
in action. Then we're going
to move on to talk about hash functions and work our way up this concept tree to talk about cryptographic
hash functions. Last, we're going to talk about message
authentication codes. So at the end of the series
on cryptography basics, you will be able to select the proper kind of
algorithm to use. One, to encrypt
sensitive data, two, to authenticate
messages, and three, to prevent data tampering. Now, we have a lot to cover,
so let's get started.