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One of the benefits
of using cryptography

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is that we can keep
our data private,

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whether it's data sitting on a
disk or sitting in the cloud,

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or whether it's data that's
being sent over a network.

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And we're going to
that with encryption.

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And the basics for encryption
involve locking and unlocking

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data.

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And think of it like this.

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Let's imagine that, I
had a chest over here,

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and had a whole bunch of
really cool stuff inside.

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And I could get a
padlock, and I could

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lock that chest
with that padlock,

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and then have it
shipped over to you.
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and then have it
shipped over to you.

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Now if you want to
open that padlock,

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I guess you could brute force
it open, but more likely,

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you're going to use a key.

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And if it's just like a simple
padlock, it's the same key.

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So we might have a couple
of copies of that same key.

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I have a key to lock it, and
use the same key to unlock it.

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That's referred to as
symmetrical encryption.

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Where we use the same exact key
to lock and unlock the data.

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And protocols that would
use symmetrical encryption,

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would include a AES, and we
use AES with several key links

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like 128, 192, 256.
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like 128, 192, 256.

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And some of the older
protocols that we used to use,

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but they're not a security
more, including Triple DES,

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are also algorithms,
encryption algorithms,

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that employ symmetrical
encryption and decryption.

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Basically, meaning using
the same key on both sides.

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And another option that we
have for encryption methods,

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is to use, what's referred
to as, asymmetrical.

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And with asymmetrical
encryption, we have a key pair.

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So I'm going to say we
have, key one, and then

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in a different color,
will have key two.
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in a different color,
will have key two.

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Now, mathematically,
these keys work together.

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And with asymmetrical
keys, whatever

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we encrypt with one key,
whether it's key one or two,

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the data can be unlocked
with the other key.

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So it's a asymmetrical,
they're not the same keys,

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but they're mathematically
paired together

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to work together.

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And with key pairs, we're going
to have private keys, which

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implies that if this is R1's
key pair, the private key,

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he never shares with
anybody, and the public key,

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he can go ahead and
share with the world.

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He can share it with
R2, he share with R3,

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he can share it with
anybody, and normally we're
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he can share it with
anybody, and normally we're

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going to share our public
key via digital certificate.

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So if R1 wanted to
encrypt data, it

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could use its private
key, which only it knows,

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shipped the data.

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And then R2, could
use R1's public key,

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I'll label that, to go
ahead and decrypt that data.

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Also public and
private key pairs

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are used as part of
digital certificates

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and authentication.

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And the big negative about
asymmetrical encryption,

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is that it does
use a lot more CPU,

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so generally, we're going to
use asymmetrical encryption
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so generally, we're going to
use asymmetrical encryption

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algorithms, like RSA for the
authentication of a peer,

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and verification of
who that peer is.

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But for the bulk
data, we're going

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to use symmetrical encryption
algorithms, like AES,

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to encrypt the bulk
of the traffic that's

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going to be sent back and
forth, between those two peers.

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And one other question
before I leave this,

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is that if we're using
asymmetrical encryption,

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we've done some work beforehand,
To generate the key pairs,

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and to get digital service,
so we can advertise

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our public key, and so forth.

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But if we're using just
symmetrical encryption,

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and we're not using asymmetrical
at all, how in the world
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and we're not using asymmetrical
at all, how in the world

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does R1 and R2, if they're
going to be VPN peers,

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how in the world do they
get the same key to lock

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and unlock the data?

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And one of the most
popular methods for them

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to establish a shared key for
the encryption and decryption

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of data, is use a technique
called Diffie-Hellman,

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which are the last names of the
two gentlemen who created it.

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So R1 and R2 could
negotiate and run

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Diffie-Hellman between them.

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Anybody could eavesdrop on
that entire conversation,

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but at the end of the
Diffie-Hellman exchange,
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but at the end of the
Diffie-Hellman exchange,

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R1 would have keys
that match what R2 has.

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And anybody who's
eavesdropping in the middle,

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wouldn't be able to figure
out the final result in keys.

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So just be aware that we have
two peers with cryptography

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that are using
shared secret keys

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that they establish
together, is primarily

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Diffie-Hellman that's used, to
dynamically generate those keys

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that both those peers can use.

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So in this video,
we've taken a look

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at the concept of encryption
to protect the data, to give us

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privacy regarding our data.

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So that only the
individuals, the parties that
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So that only the
individuals, the parties that

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have the right
keys involved, can

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correctly unlock, and actually
make sense of the data.

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So thanks for joining
me in this video.

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I'll see you in the next one.

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Meanwhile, I hope this has
been informative for you,

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and I'd like to thank
you for viewing.