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- [Instructor] Hi and
welcome back to the course.

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In this video I'm going
to quickly talk about

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what an SSH key is.

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An SSH key is a way of
encrypting information.

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Whenever you generate an SSH key there

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are two keys generated, a
public key and a private key.

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Anybody that has a public
key can decrypt information.

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If you have the public
key you can decrypt.

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Those who have the
private key can encrypt.

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What does this mean?

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You have a private key so you can use that

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to encrypt some data.

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Don't tell me about how it's encrypted but

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just know that it uses the key to encrypt.

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Then, you also have the public key so

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you can decrypt that data.

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Anybody who doesn't have the
public key cannot decrypt.

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So what you do is you
share your public key

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with those services that you
want to communicate with.

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That way if they have your public key

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they can decrypt data that you send them.

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Why is this useful?

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For example say you share your public key

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with Github, then whenever
you send them data

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that is encrypted using your private key

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they know that it's
coming from you if they

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can decrypt it because no other public key

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can decrypt your private key.

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That means that you don't
have to put your username

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and password in basically.

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In order to do that you
first need to generate

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an SSH key locally.

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It's very easy to do with
a terminal such as the get

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four bash, the bash
forget in windows or the

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terminal in mac or linux.

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You can do SSH dash key gen.

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And then that will start
generating the public

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and private key pairs.

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You can enter a file in which
you wish to save the key.

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Here I would just leave it as the default

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unless you already have other keys.

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You can have many keys and
your computer is the only

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person, not a person
really, is the only thing

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that knows the private key.

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You should generate a key
for every device you've got

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but the device itself should generate it.

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You can only generate
a key for your computer

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from the terminal.

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You can generate a key
and once that's done

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I'm gonna cancel it, but
you can continue with it.

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It may ask you for a
pass phrase, essentially

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a password that you'll have to put in

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whenever you use the key.

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You can put one in if you want
or you can leave it blank.

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After that, you can share
your public key with Github.

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The way to do that is to go
to the address, the path here

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of the public key and do
cat slash users slash jslvtr

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slash dot ssh slash id rsa dot pub.

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This is your public key, so
cat that, this one is hidden

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obvious, for obvious
reasons, but you want to

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copy all of it.

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It starts with SSH dash
rsa and it should end with

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your name at your computer.

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So copy all of it and
make sure it's copied

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and go over to Github
and you can go on your

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profile, edit your
profile, SSH and gpg keys

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and at the very top add a new SSH key.

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Here you can give it a title if you want.

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My key at my laptop,
you can give it whatever

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title you want and then
paste in the key there.

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Want to make sure that there are no spaces

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between any of the letters.

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For example, this is an I there, and then

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there's a j, you want
to make sure there's no

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space or new line between anything.

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You also don't want to
delete any characters.

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Every character is essential
and you want to make

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sure there's a new line
and a space between

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the SSH dash rsa and the
next thing and once you're

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convinced that everything is fine

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you just go and add SSH key.

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This case, it says my
key is already in use

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because I've already
added my key to Github

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but in your case it should add it fine.

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When that's done, then
you should be able to,

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when you create or edit a repository,

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for example, I've got my repository here,

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you should be able to modify
the origin if you want,

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it's not really necessary to be

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the SSH version of the url.

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When you do that you
will no longer be asked

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for your password as long
as you are in the laptop

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that you generated the SSH key with.

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Really it's just a matter
of slightly higher security.

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If you do want to do
that, make sure to use SSH

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copy all of that, like
that and then go back to

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the terminal, I'm going to
clear and then you can do

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get remote remove origin,
get remote add origin and

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paste that in.

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And that's it.

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So once you've done
that you now know a bit

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more about SSH and how it works.

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It works by sharing your
public key with others

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and keeping your private
key secret and never

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sharing it with anybody
else because if you do

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then they can encrypt
information using your

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private key and when a
service like Github can

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decrypt it, they will think
the person sending them

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data is you, because only
you should have access

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to your private key.

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If you share your private
key you can basically,

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other people can pretend to be you.

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So that's not a good thing.

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That's everything that I wanted
to tell you about SSH keys.

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Hopefully that's cleared some doubts out

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and again that's just a
small tip of the iceberg

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on what security is about
and I would encourage you

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to explore and learn more about
that if you're interested.

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That's it for this video so
thanks very much for watching.

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I'll see you in the next one.