Is everybody having a good day?
That's awesome, I'm so glad to hear that.
I had no idea how cool Roots Asylum was,
but you people have drone wars in here.
That's amazing.
Encrypted relay race, that's wonderful.
I'm here to talk to especially the kids today
about how to tell your friends about crypto.
I would love it if each and every one of you
had the chance to teach one other person about encryption,
about how you communicate with somebody else
and feel safe doing it.
Who wants to learn about that today?
That is amazing, I'm so glad to see it.
Can we get especially the little kids
up a little closer to the front?
You're gonna get a chance in the next 10 minutes
to solve your own small crypto puzzle
and learn how to teach your friends about cryptography, okay?
Come on up, there you go.
Just sit down right here, we're good.
All right, come on on up.
I have a faithful assistant today,
my own friend,
my awesome brand new husband, Deviant,
and he's gonna do us a favor
and pass out crypto puzzles to the kids up in the front.
Does that mean, there you are.
So hi, I'm Tara.
I do stuff here at DEF CON
and I'm gonna show you how to use a game
I learned when I was in elementary school
to teach other people about cryptography.
I was kind of a nerd and I like to play games too,
so this is my natural home, folks.
All right.
All right.
I like games of every kind, every stripe.
I love poker, which makes Vegas pretty fun and happy for me.
And I learned about six or seven years ago
more about cryptography than I thought I'd ever have to.
I don't do crypto normally.
Actually, most of the time,
I run a security operations center
or I do incident response.
And in security, that's about doing stuff fast.
Sometimes crypto is about doing stuff fun and slow.
So let's learn a little bit more about it.
Who knows what cryptography is?
Best guess with one word.
Best guess?
What is it?
Wonderful.
It is the study of coded messages.
That is fabulous.
What does crypto mean?
It means a secret, right?
It means something that you don't know.
Cryptography is just a secret
that you and someone else have put together
so you can hide a message and then unhide it, right?
Good.
Does anybody up here know what this crypto is right here?
You ever seen it before?
Come on, I know you know.
Caesar's cipher.
It's one of the, oh, I heard a kid's voice back there
shouting Caesar's cipher.
Come on up here and sit down.
You're gonna get a crypto puzzle in a minute.
All right, this is a Caesar's cipher.
The easiest way to explain to your friends
what cryptography is is a substitution cipher, right?
When one letter of the alphabet means a different,
different letter of the alphabet.
It's really easy to understand,
and it's something I'm gonna show you how to do today, okay?
Does anybody in here know what rot or rotate 13 means?
If a Caesar's cipher, oh, go, bring it.
Yep.
And you add 13 to it, that's wonderful.
So in rot or rotate 13, what is the letter A equal?
Does anybody know?
M. M, awesome.
I heard a little girl back there.
Come on and sit up at the front if you'd like to.
That's right, an A equals an M in rot 13,
and you're all gonna get a chance
to do this kind of puzzle in just a minute.
This is what it looks like.
It's why we call it rot or rotate.
It's just a wheel of letters just like this.
And if you want to, you can look those up
on your phones right now or any machine you have
in front of you and pull up a rot 13 alphabet, okay?
If you wanna play along, and I highly advise it,
Does anybody know why people at crypto parties
who are kinda nerds like to joke about rot 26?
What is A in rot 26?
The little girl back here.
It's A, bravo, awesome, I'm so glad you said that.
That's why it's funny, right?
If you encrypt something with rot 26,
it's just the alphabet again, and it's really funny.
Very good.
You can come to my next party.
Does anybody know what this is?
It's a box.
It's a box you can open, and it's called a,
anybody know?
Adults are allowed to guess on, cryptex, awesome, yes.
Didn't even require an adult on that one.
A cryptex, it's a box you can open
by understanding a substitution cipher, just like this one.
That's just what your locks are on your lockers
at school, by the way.
Not that I'm giving you any hints.
That's my husband's job.
He'll teach you about locks and breaking into things
in a little bit.
Does anybody know what this is?
The secret to cryptography is never being scared of it.
This is called a Vigenere cipher, and this is just where
cryptography went over the last several hundred years.
But the basis of all of these secrets is just knowing
that one letter is gonna stand for another letter, okay?
Sometimes you need a secret in crypto to be really,
really strong.
So if all you have for information is just one letter
and another letter, sometimes you add in something,
that gives your cryptography a little bit of randomness.
What is that little bit of chaos called?
Does anybody know?
You use it with pepper.
Salt, exactly.
You add a little bit of randomness,
and then you get something that only you
and somebody else can unlock.
Who's played this game before?
Mansion, apartment, shack, house.
This is so great.
I did this talk yesterday for crypto and privacy,
Village, and almost none of the boys got it there.
All the girls played Mansion, apartment, shack, house
when they were in elementary school.
And if you were like me, you counted in advance
backward in your head to make sure you ended up
with Bobby from the third grade.
So this is a game that lets you show people
how cryptography works.
It rotates in a circle, and you pick out and eliminate
the different choices that you have after you set yourself
up with Porsches and mansions and fun stuff like that.
You do it by drawing a spiral circle until someone else
who's not looking says stop, and you count the rings.
The number of rings outward is how many times
you go around the circle, right?
So you have your randomness, you're going around
in a circle, and you're eliminating choices
until you end up with a final sentence.
I live in a mansion with Bobby, and I drive a Porsche.
And I still have student loans, which most
of the adults would get, all right?
So here's the question.
This right here is the opposite of a Caesar cipher, okay?
It's A, X plus three.
A equals the letter that you're going for, plus three.
If A plus three is our crypto, what does X equal?
What is the letter you're gonna get?
Best guess?
It's the opposite.
So if a D is an A in a Caesar cipher,
what is an A in the opposite?
It's a D, good, exactly.
Now we understand.
What cryptography is is just adding stuff to this equation
until it gets so complex that people can't guess it
really easily.
Then you add the randomness in so that computers
can't guess it really easily, right?
Exactly.
Now we have a secret one person has and another person has.
In just a second, you're gonna do your own
ROT 13 translation, but I want you all to realize
the only thing cryptography is when you explain it
to your friends, and please, explain it to your parents too,
because it's an equation that lets you translate
numbers and letters, okay?
Sound pretty fair?
Not scary at all.
In fact, it's a lot of fun for puzzles and games.
So as you're sitting at your computers,
I want you to recognize that all you're doing
is just letting your computer translate a secret for you.
So for all the kids up here who wanna try their own puzzle,
I'm gonna ask Debian over here to pass out
the small slips of paper.
You already got, does everybody have a slip of paper
that wants one?
Everybody's got one that wants one?
Okay.
I would like you, if you don't have a ROT 13 alphabet
pulled up on your phone or your computer
to share with a friend and translate the secret
that I gave you, all right?
I don't know you, but I know what code you need to use
and so do you.
So give it a shot.
The first person that calls out what their secret is
and do it by yourself without your parents
or with your friends, the first person that calls that out
gets the raspberry pie I just won for knowing comic book
stuff.
What is it?
Road trip.
We have a winner of an apple pie.
Let's bring it.
Apple pie.
Wait, no, that's a raspberry pie.
I'm hungry.
I need apple pie really badly.
Congratulations.
Keep translating.
Now, there's more prizes, all right?
Come and talk to me later on if you want to try to translate
a random rotation.
What is something that a random rotation might be?
Right?
If it was the, you know, a rocket that was flying.
Rot 5. What do you think A would be in Rot 5? E, exactly. That's the answer. So I would love it if
you come up and get more advanced puzzles and try it out. For those of you that haven't tried
crypto puzzles before, try a site called rumkin.com and try translating it in all the different
rotations you can find. This is all cryptography is. It's how you keep those messages safe and
secure. Yes, I'm sure. And the thing I want you to remember is that when you get the chance,
explain to everybody that you know, crypto's not magic. It's just a little bit of math and a whole
lot of trust and the ability to talk to people and feel safe doing it. Y'all get the idea? Yes?
Awesome. I am so proud. Ask me anything you want to know. I don't do this for a living. I just
kind of get it. And if you want to know these puzzles, it's a great idea if you want to grow
up to be a hacker.
A little bit about crypto too. Thanks, kids.