Cryptographers, quantum computers and the war for information
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0:01 - 0:04I'm in the business
of safeguarding secrets, -
0:04 - 0:06and this includes your secrets.
-
0:07 - 0:09Cryptographers are
the first line of defense -
0:09 - 0:13in an ongoing war that's been
raging for centuries: -
0:13 - 0:15a war between code makers
-
0:15 - 0:17and code breakers.
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0:17 - 0:19And this is a war on information.
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0:20 - 0:24The modern battlefield
for information is digital. -
0:24 - 0:26And it wages across your phones,
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0:26 - 0:27your computers
-
0:27 - 0:28and the internet.
-
0:29 - 0:34Our job is to create systems that scramble
your emails and credit card numbers, -
0:34 - 0:37your phone calls and text messages --
-
0:37 - 0:39and that includes those saucy selfies --
-
0:39 - 0:40(Laughter)
-
0:40 - 0:43so that all of this information
can only be descrambled -
0:43 - 0:45by the recipient that it's intended for.
-
0:46 - 0:48Now, until very recently,
-
0:48 - 0:51we thought we'd won this war for good.
-
0:52 - 0:55Right now, each of your smartphones
is using encryption -
0:55 - 0:58that we thought was unbreakable
and that was going to remain that way. -
1:00 - 1:02We were wrong,
-
1:02 - 1:04because quantum computers are coming,
-
1:04 - 1:07and they're going to change
the game completely. -
1:08 - 1:11Throughout history,
cryptography and code-breaking -
1:11 - 1:13has always been this game
of cat and mouse. -
1:14 - 1:15Back in the 1500s,
-
1:15 - 1:18Queen Mary of the Scots thought
she was sending encrypted letters -
1:19 - 1:20that only her soldiers could decipher.
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1:21 - 1:23But Queen Elizabeth of England,
-
1:23 - 1:26she had code breakers
that were all over it. -
1:26 - 1:28They decrypted Mary's letters,
-
1:28 - 1:31saw that she was attempting
to assassinate Elizabeth -
1:31 - 1:34and, subsequently,
they chopped Mary's head off. -
1:36 - 1:38A few centuries later, in World War II,
-
1:39 - 1:42the Nazis communicated
using the Engima code, -
1:42 - 1:46a much more complicated encryption scheme
that they thought was unbreakable. -
1:46 - 1:48But then good old Alan Turing,
-
1:48 - 1:51the same guy who invented
what we now call the modern computer, -
1:51 - 1:54he built a machine and used it
to break Enigma. -
1:55 - 1:56He deciphered the German messages
-
1:56 - 1:59and helped to bring Hitler
and his Third Reich to a halt. -
2:00 - 2:02And so the story has gone
throughout the centuries. -
2:03 - 2:05Cryptographers improve their encryption,
-
2:05 - 2:08and then code breakers fight back
and they find a way to break it. -
2:09 - 2:12This war's gone back and forth,
and it's been pretty neck and neck. -
2:14 - 2:16That was until the 1970s,
-
2:16 - 2:19when some cryptographers
made a huge breakthrough. -
2:20 - 2:23They discovered an extremely
powerful way to do encryption -
2:23 - 2:25called "public-key cryptography."
-
2:26 - 2:30Unlike all of the prior methods used
throughout history, it doesn't require -
2:30 - 2:34that the two parties that want to send
each other confidential information -
2:34 - 2:36have exchanged the secret key beforehand.
-
2:37 - 2:41The magic of public-key cryptography
is that it allows us to connect securely -
2:41 - 2:42with anyone in the world,
-
2:43 - 2:46whether we've exchanged
data before or not, -
2:46 - 2:50and to do it so fast that you and I
don't even realize it's happening. -
2:51 - 2:54Whether you're texting your mate
to catch up for a beer, -
2:54 - 2:59or you're a bank that's transferring
billions of dollars to another bank, -
2:59 - 3:02modern encryption enables us
to send data that can be secured -
3:02 - 3:04in a matter of milliseconds.
-
3:06 - 3:08The brilliant idea that makes
this magic possible, -
3:08 - 3:11it relies on hard mathematical problems.
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3:12 - 3:15Cryptographers are deeply interested
in things that calculators can't do. -
3:17 - 3:21For example, calculators can multiply
any two numbers you like, -
3:21 - 3:22no matter how big the size.
-
3:23 - 3:25But going back the other way --
-
3:25 - 3:27starting with the product and then asking,
-
3:27 - 3:30"Which two numbers multiply
to give this one?" -- -
3:30 - 3:32that's actually a really hard problem.
-
3:33 - 3:38If I asked you to find which two-digit
numbers multiply to give 851, -
3:39 - 3:40even with a calculator,
-
3:40 - 3:43most people in this room would have
a hard time finding the answer -
3:43 - 3:45by the time I'm finished with this talk.
-
3:45 - 3:48And if I make the numbers a little larger,
-
3:48 - 3:52then there's no calculator on earth
that can do this. -
3:52 - 3:55In fact, even the world's
fastest supercomputer -
3:55 - 3:57would take longer
than the life age of the universe -
3:57 - 4:00to find the two numbers
that multiply to give this one. -
4:01 - 4:04And this problem,
called "integer factorization," -
4:04 - 4:08is exactly what each of your smartphones
and laptops is using right now -
4:08 - 4:10to keep your data secure.
-
4:10 - 4:13This is the basis of modern encryption.
-
4:14 - 4:18And the fact that all the computing power
on the planet combined can't solve it, -
4:18 - 4:21that's the reason we cryptographers
thought we'd found a way -
4:21 - 4:24to stay ahead of the code
breakers for good. -
4:25 - 4:27Perhaps we got a little cocky
-
4:28 - 4:30because just when we thought
the war was won, -
4:30 - 4:33a bunch of 20th-century physicists
came to the party, -
4:33 - 4:36and they revealed
that the laws of the universe, -
4:36 - 4:39the same laws that modern
cryptography was built upon, -
4:39 - 4:41they aren't as we thought they were.
-
4:42 - 4:46We thought that one object couldn't be
in two places at the same time. -
4:46 - 4:48It's not the case.
-
4:48 - 4:52We thought nothing can possibly spin
clockwise and anticlockwise -
4:52 - 4:53simultaneously.
-
4:53 - 4:55But that's incorrect.
-
4:55 - 4:59And we thought that two objects
on opposite sides of the universe, -
4:59 - 5:01light years away from each other,
-
5:01 - 5:05they can't possibly influence
one another instantaneously. -
5:06 - 5:07We were wrong again.
-
5:08 - 5:11And isn't that always the way
life seems to go? -
5:11 - 5:14Just when you think you've got
everything covered, your ducks in a row, -
5:14 - 5:16a bunch of physicists come along
-
5:16 - 5:19and reveal that the fundamental laws
of the universe are completely different -
5:19 - 5:21to what you thought?
-
5:21 - 5:22(Laughter)
-
5:22 - 5:23And it screws everything up.
-
5:23 - 5:28See, in the teeny tiny subatomic realm,
-
5:28 - 5:31at the level of electrons and protons,
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5:31 - 5:32the classical laws of physics,
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5:32 - 5:34the ones that we all know and love,
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5:34 - 5:36they go out the window.
-
5:36 - 5:39And it's here that the laws
of quantum mechanics kick in. -
5:40 - 5:41In quantum mechanics,
-
5:41 - 5:45an electron can be spinning clockwise
and anticlockwise at the same time, -
5:45 - 5:48and a proton can be in two places at once.
-
5:50 - 5:52It sounds like science fiction,
-
5:52 - 5:56but that's only because
the crazy quantum nature of our universe, -
5:56 - 5:58it hides itself from us.
-
5:59 - 6:02And it stayed hidden from us
until the 20th century. -
6:03 - 6:07But now that we've seen it,
the whole world is in an arms race -
6:07 - 6:10to try to build a quantum computer --
-
6:10 - 6:15a computer that can harness the power
of this weird and wacky quantum behavior. -
6:16 - 6:19These things are so revolutionary
-
6:19 - 6:21and so powerful
-
6:21 - 6:23that they'll make today's
fastest supercomputer -
6:23 - 6:25look useless in comparison.
-
6:26 - 6:29In fact, for certain problems
that are of great interest to us, -
6:30 - 6:32today's fastest supercomputer
is closer to an abacus -
6:32 - 6:34than to a quantum computer.
-
6:34 - 6:38That's right, I'm talking about
those little wooden things with the beads. -
6:38 - 6:43Quantum computers can simulate
chemical and biological processes -
6:43 - 6:46that are far beyond the reach
of our classical computers. -
6:47 - 6:52And as such, they promise to help us solve
some of our planet's biggest problems. -
6:53 - 6:56They're going to help us
combat global hunger; -
6:57 - 6:59to tackle climate change;
-
6:59 - 7:03to find cures for diseases and pandemics
for which we've so far been unsuccessful; -
7:04 - 7:07to create superhuman
artificial intelligence; -
7:08 - 7:11and perhaps even more important
than all of those things, -
7:11 - 7:15they're going to help us understand
the very nature of our universe. -
7:16 - 7:19But with this incredible potential
-
7:20 - 7:21comes an incredible risk.
-
7:23 - 7:25Remember those big numbers
I talked about earlier? -
7:26 - 7:28I'm not talking about 851.
-
7:28 - 7:30In fact, if anyone in here
has been distracted -
7:30 - 7:32trying to find those factors,
-
7:32 - 7:35I'm going to put you out of your misery
and tell you that it's 23 times 37. -
7:36 - 7:37(Laughter)
-
7:37 - 7:39I'm talking about the much
bigger number that followed it. -
7:40 - 7:44While today's fastest supercomputer
couldn't find those factors -
7:44 - 7:46in the life age of the universe,
-
7:46 - 7:49a quantum computer
could easily factorize numbers -
7:49 - 7:51way, way bigger than that one.
-
7:52 - 7:55Quantum computers will break
all of the encryption currently used -
7:55 - 7:57to protect you and I from hackers.
-
7:57 - 7:59And they'll do it easily.
-
8:01 - 8:02Let me put it this way:
-
8:02 - 8:04if quantum computing was a spear,
-
8:05 - 8:06then modern encryption,
-
8:06 - 8:10the same unbreakable system
that's protected us for decades, -
8:10 - 8:12it would be like a shield
made of tissue paper. -
8:14 - 8:18Anyone with access to a quantum computer
will have the master key -
8:18 - 8:20to unlock anything they like
in our digital world. -
8:21 - 8:23They could steal money from banks
-
8:23 - 8:25and control economies.
-
8:25 - 8:28They could power off hospitals
or launch nukes. -
8:28 - 8:32Or they could just sit back
and watch all of us on our webcams -
8:32 - 8:34without any of us knowing
that this is happening. -
8:37 - 8:41Now, the fundamental unit of information
on all of the computers we're used to, -
8:41 - 8:43like this one,
-
8:43 - 8:44it's called a "bit."
-
8:45 - 8:47A single bit can be one of two states:
-
8:47 - 8:49it can be a zero or it can be a one.
-
8:50 - 8:53When I FaceTime my mum
from the other side of the world -- -
8:54 - 8:56and she's going to kill
me for having this slide -- -
8:56 - 8:58(Laughter)
-
8:58 - 9:01we're actually just sending each other
long sequences of zeroes and ones -
9:01 - 9:05that bounce from computer to computer,
from satellite to satellite, -
9:05 - 9:07transmitting our data at a rapid pace.
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9:07 - 9:09Bits are certainly very useful.
-
9:09 - 9:12In fact, anything
we currently do with technology -
9:12 - 9:14is indebted to the usefulness of bits.
-
9:15 - 9:16But we're starting to realize
-
9:16 - 9:21that bits are really poor at simulating
complex molecules and particles. -
9:21 - 9:23And this is because, in some sense,
-
9:23 - 9:26subatomic processes can be doing
two or more opposing things -
9:27 - 9:28at the same time
-
9:28 - 9:31as they follow these bizarre rules
of quantum mechanics. -
9:31 - 9:33So, late last century,
-
9:33 - 9:36some really brainy physicists
had this ingenious idea: -
9:36 - 9:38to instead build computers
that are founded -
9:38 - 9:40on the principles of quantum mechanics.
-
9:43 - 9:46Now, the fundamental unit of information
of a quantum computer, -
9:46 - 9:47it's called a "qubit."
-
9:48 - 9:49It stands for "quantum bit."
-
9:51 - 9:54Instead of having just two states,
like zero or one, -
9:54 - 9:57a qubit can be an infinite
number of states. -
9:58 - 10:02And this corresponds to it being
some combination of both zero and one -
10:02 - 10:03at the same time,
-
10:03 - 10:06a phenomenon that we call "superposition."
-
10:07 - 10:09And when we have two qubits
in superposition, -
10:09 - 10:12we're actually working across
all four combinations -
10:12 - 10:14of zero-zero, zero-one,
one-zero and one-one. -
10:15 - 10:16With three qubits,
-
10:16 - 10:20we're working in superposition
across eight combinations, -
10:20 - 10:21and so on.
-
10:21 - 10:25Each time we add a single qubit,
we double the number of combinations -
10:25 - 10:29that we can work with in superposition
-
10:29 - 10:30at the same time.
-
10:31 - 10:34And so when we scale up
to work with many qubits, -
10:34 - 10:37we can work with an exponential
number of combinations -
10:37 - 10:39at the same time.
-
10:39 - 10:43And this just hints at where the power
of quantum computing is coming from. -
10:45 - 10:46Now, in modern encryption,
-
10:47 - 10:51our secret keys, like the two factors
of that larger number, -
10:51 - 10:54they're just long sequences
of zeroes and ones. -
10:55 - 10:56To find them,
-
10:56 - 11:00a classical computer must go through
every single combination, -
11:00 - 11:01one after the other,
-
11:01 - 11:05until it finds the one that works
and breaks our encryption. -
11:06 - 11:08But on a quantum computer,
-
11:09 - 11:12with enough qubits in superposition,
-
11:13 - 11:17information can be extracted
from all combinations at the same time. -
11:19 - 11:20In very few steps,
-
11:20 - 11:24a quantum computer can brush aside
all of the incorrect combinations, -
11:24 - 11:26home in on the correct one
-
11:26 - 11:28and then unlock our treasured secrets.
-
11:32 - 11:35Now, at the crazy quantum level,
-
11:36 - 11:39something truly incredible
is happening here. -
11:41 - 11:44The conventional wisdom
held by many leading physicists -- -
11:44 - 11:47and you've got to stay
with me on this one -- -
11:47 - 11:51is that each combination is actually
examined by its very own quantum computer -
11:51 - 11:54inside its very own parallel universe.
-
11:55 - 11:59Each of these combinations,
they add up like waves in a pool of water. -
12:00 - 12:02The combinations that are wrong,
-
12:02 - 12:04they cancel each other out.
-
12:04 - 12:06And the combinations that are right,
-
12:06 - 12:08they reinforce and amplify each other.
-
12:08 - 12:11So at the end of the quantum
computing program, -
12:11 - 12:14all that's left is the correct answer,
-
12:14 - 12:16that we can then observe
here in this universe. -
12:18 - 12:21Now, if that doesn't make
complete sense to you, don't stress. -
12:21 - 12:22(Laughter)
-
12:22 - 12:23You're in good company.
-
12:24 - 12:27Niels Bohr, one of
the pioneers of this field, -
12:27 - 12:30he once said that anyone
who could contemplate quantum mechanics -
12:30 - 12:33without being profoundly shocked,
-
12:33 - 12:34they haven't understood it.
-
12:34 - 12:36(Laughter)
-
12:36 - 12:38But you get an idea
of what we're up against, -
12:38 - 12:40and why it's now up to us cryptographers
-
12:40 - 12:41to really step it up.
-
12:43 - 12:45And we have to do it fast,
-
12:45 - 12:47because quantum computers,
-
12:47 - 12:50they already exist in labs
all over the world. -
12:51 - 12:53Fortunately, at this minute,
-
12:53 - 12:56they only exist
at a relatively small scale, -
12:56 - 12:59still too small to break
our much larger cryptographic keys. -
13:00 - 13:02But we might not be safe for long.
-
13:03 - 13:05Some folks believe that secret
government agencies -
13:05 - 13:07have already built a big enough one,
-
13:07 - 13:09and they just haven't told anyone yet.
-
13:10 - 13:12Some pundits say
they're more like 10 years off. -
13:12 - 13:14Some people say it's more like 30.
-
13:15 - 13:18You might think that
if quantum computers are 10 years away, -
13:18 - 13:21surely that's enough time
for us cryptographers to figure it out -
13:21 - 13:23and to secure the internet in time.
-
13:23 - 13:25But unfortunately, it's not that easy.
-
13:26 - 13:28Even if we ignore
the many years that it takes -
13:28 - 13:31to standardize and deploy and then
roll out new encryption technology, -
13:31 - 13:34in some ways we may already be too late.
-
13:35 - 13:39Smart digital criminals
and government agencies -
13:39 - 13:43may already be storing
our most sensitive encrypted data -
13:43 - 13:45in anticipation for
the quantum future ahead. -
13:47 - 13:49The messages of foreign leaders,
-
13:50 - 13:51of war generals
-
13:53 - 13:55or of individuals who question power,
-
13:56 - 13:57they're encrypted for now.
-
13:58 - 14:00But as soon as the day comes
-
14:00 - 14:03that someone gets their hands
on a quantum computer, -
14:03 - 14:06they can retroactively break
anything from the past. -
14:07 - 14:09In certain government
and financial sectors -
14:09 - 14:11or in military organizations,
-
14:11 - 14:14sensitive data has got to remain
classified for 25 years. -
14:14 - 14:17So if a quantum computer
really will exist in 10 years, -
14:17 - 14:20then these guys are already
15 years too late -
14:20 - 14:22to quantum-proof their encryption.
-
14:23 - 14:25So while many scientists around the world
-
14:25 - 14:28are racing to try to build
a quantum computer, -
14:28 - 14:31us cryptographers are urgently
looking to reinvent encryption -
14:31 - 14:33to protect us long before that day comes.
-
14:35 - 14:38We're looking for new,
hard mathematical problems. -
14:38 - 14:41We're looking for problems that,
just like factorization, -
14:41 - 14:44can be used on our smartphones
and on our laptops today. -
14:46 - 14:50But unlike factorization,
we need these problems to be so hard -
14:50 - 14:53that they're even unbreakable
with a quantum computer. -
14:54 - 14:58In recent years, we've been digging around
a much wider realm of mathematics -
14:58 - 15:00to look for such problems.
-
15:00 - 15:02We've been looking at numbers and objects
-
15:02 - 15:04that are far more exotic
and far more abstract -
15:04 - 15:06than the ones that you and I are used to,
-
15:06 - 15:08like the ones on our calculators.
-
15:08 - 15:10And we believe we've found
some geometric problems -
15:10 - 15:12that just might do the trick.
-
15:12 - 15:15Now, unlike those two-
and three-dimensional geometric problems -
15:15 - 15:19that we used to have to try to solve
with pen and graph paper in high school, -
15:19 - 15:23most of these problems are defined
in well over 500 dimensions. -
15:24 - 15:28So not only are they a little hard
to depict and solve on graph paper, -
15:28 - 15:32but we believe they're even
out of the reach of a quantum computer. -
15:33 - 15:35So though it's early days,
-
15:35 - 15:40it's here that we are putting our hope
as we try to secure our digital world -
15:40 - 15:42moving into its quantum future.
-
15:43 - 15:45Just like all of the other scientists,
-
15:45 - 15:47we cryptographers are tremendously excited
-
15:47 - 15:51at the potential of living in a world
alongside quantum computers. -
15:53 - 15:55They could be such a force for good.
-
15:58 - 16:02But no matter what
technological future we live in, -
16:05 - 16:10our secrets will always be
a part of our humanity. -
16:11 - 16:13And that is worth protecting.
-
16:14 - 16:15Thanks.
-
16:15 - 16:18(Applause)
- Title:
- Cryptographers, quantum computers and the war for information
- Speaker:
- Craig Costello
- Description:
-
In this glimpse into our technological future, cryptographer Craig Costello discusses the world-altering potential of quantum computers, which could shatter the limits set by today's machines -- and give code breakers a master key to the digital world. See how Costello and his fellow cryptographers are racing to reinvent encryption and secure the internet.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDxTalks
- Duration:
- 16:31
Oliver Friedman edited English subtitles for In the war for information, will quantum computers defeat cryptographers? | ||
Brian Greene edited English subtitles for In the war for information, will quantum computers defeat cryptographers? | ||
Oliver Friedman approved English subtitles for In the war for information, will quantum computers defeat cryptographers? | ||
Oliver Friedman edited English subtitles for In the war for information, will quantum computers defeat cryptographers? | ||
Camille Martínez accepted English subtitles for In the war for information, will quantum computers defeat cryptographers? | ||
Camille Martínez edited English subtitles for In the war for information, will quantum computers defeat cryptographers? | ||
Camille Martínez edited English subtitles for In the war for information, will quantum computers defeat cryptographers? | ||
Joseph Geni edited English subtitles for In the war for information, will quantum computers defeat cryptographers? |