-
Not Synced
I'm in the business
of safeguarding secrets,
-
Not Synced
and this includes your secrets.
-
Not Synced
Cryptographers are
the first line of defense
-
Not Synced
in an ongoing war that's been
raging for centuries,
-
Not Synced
a war between codemakers and codebreakers.
-
Not Synced
And this is a war on information.
-
Not Synced
The modern battlefield
for information is digital,
-
Not Synced
and it wages across your phones,
-
Not Synced
your computers and the internet.
-
Not Synced
Our job is to create systems that scramble
your emails and credit card numbers,
-
Not Synced
your phone calls and text messages,
-
Not Synced
and that includes those saucy selfies,
-
Not Synced
so that all of this information
can only be de-scrambled
-
Not Synced
by the recipient that it's intended for.
-
Not Synced
Now until very recently,
-
Not Synced
we thought we'd won this war for good.
-
Not Synced
Right now, each of your smartphones
is using encryption
-
Not Synced
that we thought was unbreakable
and that was going to remain that way.
-
Not Synced
We were wrong,
-
Not Synced
because quantum computers are coming
-
Not Synced
and they're going to change
the game completely.
-
Not Synced
Throughout history,
cryptography and codebreaking
-
Not Synced
has always been this game
of cat and mouse.
-
Not Synced
Back in the 1500s,
-
Not Synced
Queen Mary of the Scots thought she
was sending encrypted letters
-
Not Synced
that only her soldiers could decipher,
-
Not Synced
but Queen Elizabeth of England,
-
Not Synced
she had codebreakers
that were all over it.
-
Not Synced
They decrypted Mary's letters,
-
Not Synced
saw that she was attempting
to assassinate Elizabeth,
-
Not Synced
and subsequently
they chopped Mary's head off.
-
Not Synced
A few centuries later, in World War II,
-
Not Synced
the Nazis communicated
using the Engima code,
-
Not Synced
a much more complicated encryption scheme
that they thought was unbreakable,
-
Not Synced
but then good old Alan Turing,
-
Not Synced
the same guy who invented
what we now call the modern computer,
-
Not Synced
he built a machine and used it
to break Enigma.
-
Not Synced
He deciphered the German messages
-
Not Synced
and helped to bring Hitler
and his Third Reich to a halt.
-
Not Synced
And so the story has gone
throughout the centuries.
-
Not Synced
Cryptographers
improve their encryption,
-
Not Synced
and then codebreakers fight back
and they find a way to break it.
-
Not Synced
This war's gone back and forth,
and it's been pretty neck-and-neck.
-
Not Synced
That was, until the 1970s,
-
Not Synced
when some cryptographers
made a huge breakthrough.
-
Not Synced
They discovered an extremely
powerful way to do encryption
-
Not Synced
called public key cryptography.
-
Not Synced
Now, unlike all of the prior methods
used throughout history,
-
Not Synced
it doesn't require that the two parties
-
Not Synced
that want to send each other
confidential information
-
Not Synced
have exchanged the secret key beforehand.
-
Not Synced
The magic of public key cryptography
is that it allows us to connect securely
-
Not Synced
with anyone in the world
-
Not Synced
whether we've exchanged
data before or not,
-
Not Synced
and to do it so fast that you and I
don't even realize that it's happening.
-
Not Synced
Whether you're texting your mate
to catch up for a beer,
-
Not Synced
or you're a bank
-
Not Synced
that's transferring billions
of dollars to another bank,
-
Not Synced
modern encryption enables us
to send data that can be secured
-
Not Synced
in a matter of milliseconds.
-
Not Synced
The brilliant idea that makes
this magic possible,
-
Not Synced
it relies on hard mathematical problems.
-
Not Synced
in a matter of milliseconds.
-
Not Synced
Cryptographers are deeply interested
in things that calculators can't do.
-
Not Synced
For example, calculators can multiply
any two numbers you like,
-
Not Synced
no matter how big the size,
-
Not Synced
but going back the other way,
-
Not Synced
starting with the product
-
Not Synced
and then asking, which two numbers
multiply to give this one,
-
Not Synced
that's actually a really hard problem.
-
Not Synced
If I asked you to find
which two-digit numbers
-
Not Synced
multiply to give 851,
even with a calculator,
-
Not Synced
most people in this room
would have a hard time
-
Not Synced
finding the answer by the time
I'm finished with this talk.
-
Not Synced
And if I make the numbers a little larger,
-
Not Synced
then there's no calculator on Earth
-
Not Synced
that can do this.
-
Not Synced
In fact, even the world's
fastest supercomputer
-
Not Synced
would take longer
than the life age of the universe
-
Not Synced
to find the two numbers
that multiply to give this one.
-
Not Synced
And this problem,
called integer factorization,
-
Not Synced
is exactly what each of your smartphones
and laptops is using right now
-
Not Synced
to keep your data secure.
-
Not Synced
This is the basis of modern encryption,
-
Not Synced
and the fact that all of the computing
power on the planet can't solve it,
-
Not Synced
that's the reason we cryptographers
-
Not Synced
thought we'd found a way to stay ahead
of the codebreakers for good.
-
Not Synced
Perhaps we got a little cocky,
-
Not Synced
because just when we thought
the war was won,
-
Not Synced
a bunch of 20th century physicists
came to the party
-
Not Synced
and they revealed
that the laws of the universe,
-
Not Synced
the same laws that modern
cryptography was built upon,
-
Not Synced
they aren't as we thought they were.
-
Not Synced
We thought that one object couldn't be
in two places at the same time.
-
Not Synced
It's not the case.
-
Not Synced
We thought nothing can possibly spin
clockwise and anti-clockwise
-
Not Synced
simultaneously,
-
Not Synced
but that's incorrect.
-
Not Synced
And we thought that two objects
-
Not Synced
on opposite sides of the universe,
light years away from each other,
-
Not Synced
they can't possible influence
one another instantaneously.
-
Not Synced
We were wrong again.
-
Not Synced
And isn't that always the way
life seems to go?
-
Not Synced
Just when you think
you've got everything covered,
-
Not Synced
you've got your ducks in a row,
-
Not Synced
a bunch of physicists come along
-
Not Synced
and reveal that the fundamental
laws of the universe
-
Not Synced
are completely different
to what you thought?
-
Not Synced
(Laughter)
-
Not Synced
And it screws everything up.
-
Not Synced
See, in the teeny tiny subatomic realm,
-
Not Synced
at the level of electrons and protons,
-
Not Synced
the classical laws of physics,
-
Not Synced
the ones that we all know and love,
-
Not Synced
they go out the window,
-
Not Synced
and it's here that the laws
of quantum mechanics kick in.
-
Not Synced
In quantum mechanics, an electron
-
Not Synced
can be spinning clockwise
and anti-clockwise at the same time
-
Not Synced
and a proton can be in two places at once.
-
Not Synced
It sounds like science fiction,
-
Not Synced
but that's only because
the crazy quantum nature of our universe,
-
Not Synced
it hides itself from us.
-
Not Synced
And it stayed hidden from us
until the 20th century.
-
Not Synced
But now that we've seen it,
the whole world is in an arms race
-
Not Synced
to try to build a quantum computer,
-
Not Synced
a computer that can harness the power
of this weird and wacky quantum behavior.
-
Not Synced
These things are so revolutionary
-
Not Synced
and so powerful
-
Not Synced
that they'll make today's
fastest supercomputer
-
Not Synced
look useless in comparison.
-
Not Synced
In fact, for certain problems
that are of great interest to us,
-
Not Synced
today's fastest supercomputer
is closer to an abacus
-
Not Synced
than to a quantum computer.
-
Not Synced
That's right, I'm talking about
those little wooden things with the beads.
-
Not Synced
Quantum computers can simulate
chemical and biological processes
-
Not Synced
that are far beyond the reach
of our classical computers,
-
Not Synced
and as such, they promise to help us solve
some of our planet's biggest problems.
-
Not Synced
They're going to help us
combat global hunger,
-
Not Synced
to tackle climate change,
-
Not Synced
to find cures for diseases and pandemics
for which we've so far been unsuccessful,
-
Not Synced
to create superhuman
artificial intelligence,
-
Not Synced
and perhaps even more important
than all of those things,
-
Not Synced
they're going to help us understand
the very nature of our universe.
-
Not Synced
But with this incredible potential
-
Not Synced
comes an incredible risk.
-
Not Synced
Remember those big numbers
I talked about earlier?
-
Not Synced
I'm not talking about 851.
-
Not Synced
In fact, if anyone in here
has been distracted
-
Not Synced
trying to find those factors,
-
Not Synced
I'm going to put you out of your misery
and tell you that it's 23 times 37.
-
Not Synced
(Laughter)
-
Not Synced
I'm talking about the much
bigger number that followed it.
-
Not Synced
While today's fastest supercomputer
couldn't find those factors
-
Not Synced
in the life's age of the universe,
-
Not Synced
a quantum computer
could easily factorize numbers
-
Not Synced
way, way bigger than that one.
-
Not Synced
Quantum computers will break
all of the encryption
-
Not Synced
currently used to protect
you and I from hackers,
-
Not Synced
and they'll do it easily.
-
Not Synced
Let me put it this way:
-
Not Synced
if quantum computing was a spear,
-
Not Synced
then modern encryption,
-
Not Synced
the same unbreakable system
that's protected us for decades,
-
Not Synced
it would be like a shield
made of tissue paper.
-
Not Synced
Anyone with access to a quantum computer
-
Not Synced
will have the master key to unlock
anything they like in our digital world.
-
Not Synced
They could steal money from banks
-
Not Synced
and control economies.
-
Not Synced
They could power off hospitals
or launch nukes,
-
Not Synced
or they could just sit back
and watch all of us on our webcams
-
Not Synced
without any of us knowing
that this is happening.
-
Not Synced
Now, the fundamental unit of information
on all of the computers we're used to,
-
Not Synced
like this one,
-
Not Synced
it's called a bit.
-
Not Synced
A single bit can be one of two states.
-
Not Synced
It can be a zero or it can be a one.
-
Not Synced
When I FaceTime my mum
from the other side of the world,
-
Not Synced
and she's going to kill me
for having this slide (Laughter)
-
Not Synced
we're actually just sending each other
long sequences of zeroes and ones
-
Not Synced
that bounce from computer to computer,
from satellite to satellite,
-
Not Synced
transmitting our data at a rapid pace.
-
Not Synced
Bits are certainly very useful.
-
Not Synced
In fact, anything
we currently do with technology
-
Not Synced
is indebted to the usefulness of bits.
-
Not Synced
But we're starting to realize
that bits are really poor
-
Not Synced
at simulating complex
molecules and particles,
-
Not Synced
and this is because in some sense
-
Not Synced
subatomic processes can be doing
two or more opposing things
-
Not Synced
at the same time
-
Not Synced
as they follow these bizarre
rules of quantum mechanics.
-
Not Synced
So late last century,
-
Not Synced
some really brainy physicists
had this ingenious idea:
-
Not Synced
to instead build computers
that are founded
-
Not Synced
on the principles of quantum mechanics.
-
Not Synced
Now, the fundamental unit of information
of a quantum computer,
-
Not Synced
it's called a qubit.
-
Not Synced
It stands for "quantum bit."
-
Not Synced
Instead of having just two states,
like zero or one,
-
Not Synced
a qubit can be an infinite
number of states,
-
Not Synced
and this corresponds to it being
some combination of both zero and one
-
Not Synced
at the same time,
-
Not Synced
a phenomenon that we call superposition.
-
Not Synced
And when we have two qubits
in superposition,
-
Not Synced
we're actually working across
all four combinations
-
Not Synced
of zero-zero, zero-one,
one-zero and one-one.
-
Not Synced
With three qubits,
-
Not Synced
we're working in superposition
across eight combinations,
-
Not Synced
and so on.
-
Not Synced
Each time we add a single qubit,
-
Not Synced
we double the number of combinations
-
Not Synced
that we can work with
in superposition at the same time.
-
Not Synced
And so when we scale up to work
with many qubits,
-
Not Synced
we can work with an exponential
number of combinations
-
Not Synced
at the same time.
-
Not Synced
And this just hints at where the power
of quantum computing is coming from.
-
Not Synced
Now, in modern encryption,
-
Not Synced
our secret keys,
-
Not Synced
like the two factors
of that larger number,
-
Not Synced
they're just long sequences
of zeroes and ones.
-
Not Synced
To find them, a classical computer
-
Not Synced
must go through every single combination
-
Not Synced
one after the other
-
Not Synced
until it finds the one that works
and breaks our encryption.
-
Not Synced
But on a quantum computer,
-
Not Synced
with enough qubits in superposition,
-
Not Synced
information can be extracted
from all combinations at the same time.
-
Not Synced
In very few steps, a quantum computer
-
Not Synced
can brush aside all of
the incorrect combinations,
-
Not Synced
home in on the correct one,
-
Not Synced
and then unlock our treasured secrets.
-
Not Synced
Now, at the crazy quantum level,
-
Not Synced
something truly incredible
is happening here.
-
Not Synced
The conventional wisdom
held by many leading physicists --
-
Not Synced
and you've got to stay
with me on this one --
-
Not Synced
is that each combination is actually
examined by its own quantum computer
-
Not Synced
inside its very own parallel universe.
-
Not Synced
Each of these combinations,
they add up like waves in a pool of water.
-
Not Synced
The combinations that are wrong,
-
Not Synced
they cancel each other out,
-
Not Synced
and the combinations that are right,
-
Not Synced
they reinforce and amplify each other.
-
Not Synced
So at the end of
the quantum computing program,
-
Not Synced
all that's left is the correct answer
-
Not Synced
that we can then observe
here in this universe.
-
Not Synced
Now if that doesn't make
complete sense to you, don't stress.
-
Not Synced
(Laughter)
-
Not Synced
You're in good company.
-
Not Synced
Niels Bohr, one of
the pioneers of this field,
-
Not Synced
he once said that anyone
who could contemplate quantum mechanics
-
Not Synced
without being profoundly shocked,
they haven't understood it.
-
Not Synced
(Laughter)
-
Not Synced
But you get an idea
of what we're up against
-
Not Synced
and why it's now up to us cryptographers
-
Not Synced
to really step it up.
-
Not Synced
And we have to do it fast,
-
Not Synced
because quantum computers,
-
Not Synced
they already exist in labs
all over the world.
-
Not Synced
Fortunately, at this minute,
-
Not Synced
they only exist
at a relatively small scale,
-
Not Synced
still too small to break
our much larger cryptographic keys,
-
Not Synced
but we might not be safe for long.
-
Not Synced
Some folks believe that secret
government agencies
-
Not Synced
have already built a big enough one
-
Not Synced
and they just haven't told anyone yet.
-
Not Synced
Some punters say
they're more like 10 years off.
-
Not Synced
Some people say it's more like 30.
-
Not Synced
And you might think that
if quantum computers are 10 years away,
-
Not Synced
surely that's enough time
for us cryptographers
-
Not Synced
to figure it out and
to secure the internet in time.
-
Not Synced
But unfortunately it's not that easy.
-
Not Synced
Even if we ignore the many years
that it takes to standardize and deploy
-
Not Synced
and then roll out
new encryption technology,
-
Not Synced
in some ways we may already be too late.
-
Not Synced
Smart digital criminals
and government agencies
-
Not Synced
may already be storing
our most sensitive encrypted data
-
Not Synced
in anticipation for
the quantum future ahead.
-
Not Synced
The messages of foreign leaders,
-
Not Synced
of war generals,
-
Not Synced
or of individuals who question power,
-
Not Synced
they're encrypted for now,
-
Not Synced
but as soon as the day comes
-
Not Synced
that someone gets their hands
on a quantum computer,
-
Not Synced
they can retroactively break
anything from the past.
-
Not Synced
In certain government
and financial sectors
-
Not Synced
or in military organizations,
-
Not Synced
sensitive data has got
to remain classified for 25 years.
-
Not Synced
So if a quantum computer
really will exist in 10 years,
-
Not Synced
then these guys are already
15 years too late
-
Not Synced
to quantum-proof their encryption.
-
Not Synced
So while many scientists around the world
-
Not Synced
are racing to try to build
a quantum computer,
-
Not Synced
us cryptographers are urgently
looking to reinvent encryption
-
Not Synced
to protect us long before that day comes.
-
Not Synced
We're looking for new,
hard mathematical problems.
-
Not Synced
We're looking for problems that,
just like factorization,
-
Not Synced
can be used on our smartphones
and on our laptops today.
-
Not Synced
But unlike factorization,
we need these problems to be so hard
-
Not Synced
that they're even unbreakable
with a quantum computer.
-
Not Synced
In recent years, we've been digging
around a much wider realm of mathematics
-
Not Synced
to look for such problems.
-
Not Synced
We've been looking at numbers and objects
-
Not Synced
that are far more exotic
and far more abstract
-
Not Synced
than the ones that you and I are used to,
-
Not Synced
like the ones on our calculators.
-
Not Synced
And we believe we've found
some geometric problems
-
Not Synced
that just might do the trick.
-
Not Synced
Now, unlike those two-
and three-dimensional geometric problems
-
Not Synced
that we used to have to try to solve
with pen and graph paper in high school,
-
Not Synced
most of these problems are defined
in well over 500 dimensions.
-
Not Synced
So not only are they a little hard
to depict and solve on graph paper,
-
Not Synced
but we believe they're even
out of the reach of a quantum computer.
-
Not Synced
So though it's early days,
-
Not Synced
it's here that we are putting our hope
as we try to secure our digital world
-
Not Synced
moving into its quantum future.
-
Not Synced
Just like all of the other scientists,
-
Not Synced
we cryptographers are tremendously excited
-
Not Synced
at the potential of living in a world
alongside quantum computers.
-
Not Synced
They could be such a force for good.
-
Not Synced
But no matter what
technological future we live in,
-
Not Synced
our secrets
-
Not Synced
will always be a part of our humanity,
-
Not Synced
and that is worth protecting.
-
Not Synced
Thanks.
-
Not Synced
(Applause)