In the war for information, will quantum computers defeat cryptographers? | Craig Costello

Translator: Joseph Geni Reviewer: Camille Martínez

翻译人员: Nan Yang 校对人员: Jiasi Hao

I'm in the business of safeguarding secrets,

我从事保护秘密的工作，

and this includes your secrets.

其中就包括你们的秘密。

Cryptographers are the first line of defense

密码学家是数百年来

in an ongoing war that's been raging for centuries:

持续不断的战争中的 第一道防线：

a war between code makers

是代码编写者

and code breakers.

和代码破译者之间的战争。

这是一场信息战争。

And this is a war on information.

The modern battlefield for information is digital.

现代信息战场是数字化的。

And it wages across your phones,

它发动于你的手机，

your computers

你的电脑

and the internet.

和互联网。

Our job is to create systems that scramble your emails and credit card numbers,

我们的工作是建立系统， 来打乱你们的电子邮件内容，

your phone calls and text messages --

信用卡号，电话内容和短信——

and that includes those saucy selfies --

这包括那些搞笑的自拍照——

(Laughter)

（笑声）

so that all of this information can only be descrambled

这样，所有的这些信息

by the recipient that it's intended for.

只能由预期的接收者解密。

一直以来，

Now, until very recently,

we thought we'd won this war for good.

我们都一直以为自己 永远赢得了这场战争。

Right now, each of your smartphones is using encryption

现在，你们每个人的手机都在使用

that we thought was unbreakable and that was going to remain that way.

我们认为永远 无法被破解的加密手段，

We were wrong,

我们错了，

because quantum computers are coming,

因为量子计算机即将加入这场战争，

and they're going to change the game completely.

它们会彻底改变游戏规则。

Throughout history, cryptography and code-breaking

纵观历史， 密码学和密码破解

has always been this game of cat and mouse.

一直是猫和老鼠的游戏。

Back in the 1500s,

回到十五世纪，

Queen Mary of the Scots thought she was sending encrypted letters

苏格兰的玛丽女王认为 她正在发送

只有她的士兵可以破解的加密信件。

that only her soldiers could decipher.

但是英格兰的伊丽莎白女王

But Queen Elizabeth of England,

she had code breakers that were all over it.

手下有无数的密码破译者。

They decrypted Mary's letters,

他们破解了玛丽的信件，

saw that she was attempting to assassinate Elizabeth

发现了她正试图刺杀伊丽莎白，

and, subsequently, they chopped Mary's head off.

随后，他们砍掉了玛丽的头。

A few centuries later, in World War II,

几个世纪之后的第二次世界大战，

the Nazis communicated using the Engima code,

纳粹使用恩尼格玛密码进行通讯，

a much more complicated encryption scheme that they thought was unbreakable.

是一种他们认为牢不可破的 更复杂的加密机制。

But then good old Alan Turing,

但是之后的艾伦·图灵，

the same guy who invented what we now call the modern computer,

那个发明了我们 称为现代计算机的人，

he built a machine and used it to break Enigma.

制作了一个机器， 用它来破解恩尼格玛。

He deciphered the German messages

他破译了德国人的消息，

并协助使得希特勒和 他的第三帝国停滞不前。

and helped to bring Hitler and his Third Reich to a halt.

And so the story has gone throughout the centuries.

这种故事已经重复了多个世纪。

Cryptographers improve their encryption,

密码学家不断改善他们的加密方式，

and then code breakers fight back and they find a way to break it.

然后密码破译者进行反击， 找到一种方法来破解它。

This war's gone back and forth, and it's been pretty neck and neck.

这场战争来来回回， 而且双方差不多并驾齐驱。

That was until the 1970s,

直到 19 世纪 70 年代，

when some cryptographers made a huge breakthrough.

一些密码学家取得了巨大的突破。

They discovered an extremely powerful way to do encryption

他们发现了一种 非常强大的加密方式，

called "public-key cryptography."

叫做“公钥密码学”。

Unlike all of the prior methods used throughout history, it doesn't require

与之前用过的所有方式不同，

它不需要想要交换 秘密信息的通讯双方

that the two parties that want to send each other confidential information

have exchanged the secret key beforehand.

提前交换密钥。

The magic of public-key cryptography is that it allows us to connect securely

公钥密码学的魔力在于， 它允许我们安全地

with anyone in the world,

与世界上任何人连接起来，

whether we've exchanged data before or not,

无论我们事先交换过数据与否，

and to do it so fast that you and I don't even realize it's happening.

它能让我们可以快速地通讯， 甚至没有意识到它正在发生。

无论你正给同伴发短信相约喝酒，

Whether you're texting your mate to catch up for a beer,

or you're a bank that's transferring billions of dollars to another bank,

还是你正在转账 数十亿美元到另一家银行，

modern encryption enables us to send data that can be secured

现代加密技术使 我们能够在几毫秒内

in a matter of milliseconds.

发送被保护的数据。

The brilliant idea that makes this magic possible,

使这个魔法成为可能的绝妙主意，

it relies on hard mathematical problems.

依赖于困难的数学问题。

Cryptographers are deeply interested in things that calculators can't do.

密码学家对计算器无法 做到的事情深感兴趣。

For example, calculators can multiply any two numbers you like,

例如，计算器可以让 你喜欢的任何两个数字相乘，

no matter how big the size.

无论数字有多大。

But going back the other way --

但是反过来——

starting with the product and then asking,

有相乘后的结果，然后问

"Which two numbers multiply to give this one?" --

“哪两个数字相乘得出的这个数字？”

that's actually a really hard problem.

这实际上是个非常难的问题。

If I asked you to find which two-digit numbers multiply to give 851,

如果我让你找出 哪两个两位数相乘等于 851，

即使有计算器，

even with a calculator,

most people in this room would have a hard time finding the answer

这个房间里的大多数人 在我完成本次演讲之前，

都很难找到答案。

by the time I'm finished with this talk.

And if I make the numbers a little larger,

而且如果我让数字变得更大些，

then there's no calculator on earth that can do this.

地球上没有任何计算器可以做到。

In fact, even the world's fastest supercomputer

实际上，甚至是世界上 最快的超级电脑

would take longer than the life age of the universe

要找到两个相乘得到该数字的数字

to find the two numbers that multiply to give this one.

将花费比宇宙寿命更长的时间。

而这个问题，被叫做“整数分解”，

And this problem, called "integer factorization,"

is exactly what each of your smartphones and laptops is using right now

就是现在你们每部手机和电脑 正在用来保护你们的

to keep your data secure.

数据安全的方法。

This is the basis of modern encryption.

这是现代加密的基础。

And the fact that all the computing power on the planet combined can't solve it,

而地球上所有计算能力联合起来 也无法解决这个问题的事实

that's the reason we cryptographers thought we'd found a way

正是我们密码学家认为 我们找到了一种方式

能永远领先于编码破坏者的原因。

to stay ahead of the code breakers for good.

也许我们有点自大，

Perhaps we got a little cocky

because just when we thought the war was won,

因为就在我们以为战争胜利的时候，

a bunch of 20th-century physicists came to the party,

一批 20 世纪的物理学家 也加入了进来，

and they revealed that the laws of the universe,

他们揭示了宇宙的定律

the same laws that modern cryptography was built upon,

并不是我们想象的那样，

they aren't as we thought they were.

而现代密码学的建立 就基于这些定律。

We thought that one object couldn't be in two places at the same time.

我们认为一个物体 不能同时处于两个地方。

It's not the case.

事实并非如此。

We thought nothing can possibly spin clockwise and anticlockwise

我们认为没有任何东西可以

同时进行顺时针和逆时针旋转。

simultaneously.

But that's incorrect.

但这也不是正确的。

And we thought that two objects on opposite sides of the universe,

我们认为分别位于 宇宙两侧的两个物体

light years away from each other,

彼此相距若干光年，

they can't possibly influence one another instantaneously.

它们不可能瞬间相互影响。

We were wrong again.

我们又错了。

And isn't that always the way life seems to go?

生活也总是这样，不是吗？

Just when you think you've got everything covered, your ducks in a row,

就在你认为你搞定了所有事情， 万事俱备的时候，

一批物理学家出现，

a bunch of physicists come along

并揭示了宇宙的基本定律

and reveal that the fundamental laws of the universe are completely different

与你想的完全不同？

（笑声）

它搞砸了一切。

to what you thought?

(Laughter)

And it screws everything up.

See, in the teeny tiny subatomic realm,

结果就是，在微小的亚原子领域，

at the level of electrons and protons,

在电子和质子的级别上，

the classical laws of physics,

我们都熟知和热爱的

the ones that we all know and love,

物理的经典定律，

they go out the window.

不复存在。

And it's here that the laws of quantum mechanics kick in.

而量子力学定律就在这里展开。

In quantum mechanics,

在量子力学中，

an electron can be spinning clockwise and anticlockwise at the same time,

电子可以同时进行 顺时针和逆时针旋转，

and a proton can be in two places at once.

而一个质子可以 同时处于两个位置。

It sounds like science fiction,

这听起来像科幻小说，

but that's only because the crazy quantum nature of our universe,

但是这仅仅是因为 宇宙的疯狂量子本质，

it hides itself from us.

对我们隐藏了自己，

And it stayed hidden from us until the 20th century.

直到 20 世纪。

But now that we've seen it, the whole world is in an arms race

但是现在我们看见了， 整个世界

都在争相尝试建造量子计算机——

to try to build a quantum computer --

a computer that can harness the power of this weird and wacky quantum behavior.

一种能够利用古怪的 量子行为力量的计算机。

These things are so revolutionary

这些东西太具有颠覆性了，

and so powerful

而且如此强大，

that they'll make today's fastest supercomputer

会使得现在最快的超级计算机

look useless in comparison.

相比之下看起来毫无用处。

In fact, for certain problems that are of great interest to us,

实际上，对于我们非常 感兴趣的某些问题，

today's fastest supercomputer is closer to an abacus

如今最快的超级电脑 更接近于一个算盘，

than to a quantum computer.

而不是量子计算机。

That's right, I'm talking about those little wooden things with the beads.

是的，我说的就是那种 带有珠子的小小的木制品。

Quantum computers can simulate chemical and biological processes

量子计算机可以 模拟化学和生物过程，

that are far beyond the reach of our classical computers.

这远远超出了传统计算机的范围。

And as such, they promise to help us solve some of our planet's biggest problems.

因此，它们很可能会帮助我们 解决地球上一些最大的问题。

They're going to help us combat global hunger;

他们将帮助我们战胜全球饥饿；

应对气候变化，

to tackle climate change;

to find cures for diseases and pandemics for which we've so far been unsuccessful;

找到我们迄今为止未能成功的 治疗疾病和全球性传染病的方法，

to create superhuman artificial intelligence;

创造超人类的人工智能，

以及比所有这些事情都重要的，

and perhaps even more important than all of those things,

they're going to help us understand the very nature of our universe.

它将帮助我们理解宇宙的本质。

But with this incredible potential

但是伴随着不可思议的潜力，

comes an incredible risk.

也带来了不可思议的风险。

Remember those big numbers I talked about earlier?

还记得我之前说过的大数字吗？

I'm not talking about 851.

我现在说的不是 851。

实际上，如果你们任何人

In fact, if anyone in here has been distracted

因为要找到这些因数而分心，

trying to find those factors,

I'm going to put you out of your misery and tell you that it's 23 times 37.

我要把你从苦难中解救出来， 告诉你答案是 23 乘 37 。

(Laughter)

（笑声）

I'm talking about the much bigger number that followed it.

我要说的是比那大得多的数字。

While today's fastest supercomputer couldn't find those factors

虽然当今最快的超级计算机 无法在宇宙生命周期中

in the life age of the universe,

找到那些因数，

a quantum computer could easily factorize numbers

但一个量子计算机可以轻易的

way, way bigger than that one.

分解比那大很多很多的数字。

Quantum computers will break all of the encryption currently used

量子计算机将打破我们现在 用来保护大家免受

to protect you and I from hackers.

黑客攻击的所有加密算法。

And they'll do it easily.

它们会轻松做到的。

Let me put it this way:

让我这样说吧：

if quantum computing was a spear,

如果量子计算是一根长矛，

then modern encryption,

那么现代加密——

the same unbreakable system that's protected us for decades,

几十年来一直保护着我们的 牢不可破的系统，

it would be like a shield made of tissue paper.

就像是纸巾做的盾牌。

Anyone with access to a quantum computer will have the master key

有权访问量子计算机的任何人 都将拥有万能钥匙，

to unlock anything they like in our digital world.

可以解锁他们在数字化世界中 喜欢的任何东西。

They could steal money from banks

他们可以从银行偷钱，

并控制经济，

and control economies.

They could power off hospitals or launch nukes.

他们可以关闭医院电源， 或者发射核武器，

Or they could just sit back and watch all of us on our webcams

或者他们可以只是坐下来， 通过网络摄像头看着我们，

without any of us knowing that this is happening.

而我们没有人知道发生了什么。

Now, the fundamental unit of information on all of the computers we're used to,

我们习惯使用的 所有计算机上的基本信息单元，

like this one,

像这个，

it's called a "bit."

叫做一个“比特”。

A single bit can be one of two states:

一个比特可以处于两个状态之一：

it can be a zero or it can be a one.

它可以是 0 或者 1。

When I FaceTime my mum from the other side of the world --

当我和地球另一端的妈妈 视频的时候——

and she's going to kill me for having this slide --

她会因为我做了 这张幻灯片杀了我的——

(Laughter)

（笑声）

we're actually just sending each other long sequences of zeroes and ones

我们实际上只是在给彼此 发送一长串的 0 和 1，

that bounce from computer to computer, from satellite to satellite,

在计算机之间，卫星之间反复，

高速地传输着我们的数据。

transmitting our data at a rapid pace.

Bits are certainly very useful.

比特当然非常有用。

In fact, anything we currently do with technology

实际上，我们现在 技术上做的任何事情

is indebted to the usefulness of bits.

都多亏了比特。

But we're starting to realize

但是我们开始意识到，

that bits are really poor at simulating complex molecules and particles.

在模拟复杂的分子和粒子方面， 比特做得很差。

And this is because, in some sense,

这是因为，在某种意义上，

subatomic processes can be doing two or more opposing things

亚原子过程可以同时做两个或更多

at the same time

相反的事情，

as they follow these bizarre rules of quantum mechanics.

因为他们遵循量子力学的 这些怪异规则。

So, late last century,

所以，上个世纪后期，

some really brainy physicists had this ingenious idea:

一些非常聪明的物理学家

有了这个巧妙的想法：

to instead build computers that are founded

建立基于量子力学原理的计算机。

on the principles of quantum mechanics.

Now, the fundamental unit of information of a quantum computer,

量子计算机的基本信息单位

it's called a "qubit."

叫做一个“量子比特” （qubit），

It stands for "quantum bit."

是 “quantum bit”的缩写。

Instead of having just two states, like zero or one,

一个量子比特可以有无限个状态，

而不再是只有 0 或 1 两个状态。

a qubit can be an infinite number of states.

And this corresponds to it being some combination of both zero and one

这对应于它同时是 0 和 1 的

at the same time,

某种组合，

a phenomenon that we call "superposition."

我们称这种现象为“叠加”。

And when we have two qubits in superposition,

当我们有两个量子比特 叠加在一起时，

we're actually working across all four combinations

实际上，我们正在研究四种组合，

of zero-zero, zero-one, one-zero and one-one.

0 - 0 ，0 - 1 ，1 - 0 ，和 1 - 1。

With three qubits,

有三个量子比特时，

we're working in superposition across eight combinations,

我们在研究八种组合的叠加状态，

and so on.

以此类推。

Each time we add a single qubit, we double the number of combinations

每次我们增加一个量子比特， 我们需要同时处理的

叠加状态的组合数量

that we can work with in superposition

将加倍。

at the same time.

所以当我们扩大规模， 处理很多量子比特时，

And so when we scale up to work with many qubits,

we can work with an exponential number of combinations

我们需要同时处理的

组合状态数量呈指数型增加。

at the same time.

And this just hints at where the power of quantum computing is coming from.

而这就暗示了量子计算的 力量从何而来。

Now, in modern encryption,

如今，在现代加密中，

our secret keys, like the two factors of that larger number,

我们的密钥， 例如大数的分解因子，

they're just long sequences of zeroes and ones.

它们只是 0 和 1 的长序列。

To find them,

为了找到它们，

a classical computer must go through every single combination,

一个传统计算机必须 实验所有的组合可能，

one after the other,

一个接着一个，

until it finds the one that works and breaks our encryption.

直到找到那对可以 成功破译加密的组合。

But on a quantum computer,

但是在量子计算机中，

with enough qubits in superposition,

有了足够多的 叠加状态的量子比特，

可以在同一时间 从所有组合中提取信息。

information can be extracted from all combinations at the same time.

In very few steps,

只需几个步骤，

a quantum computer can brush aside all of the incorrect combinations,

一个量子计算机就可以 撇开所有不正确的组合，

home in on the correct one

留住正确的那个，

and then unlock our treasured secrets.

然后解锁我们珍贵的秘密。

Now, at the crazy quantum level,

在疯狂的量子级别，

something truly incredible is happening here.

着实令人难以置信的事情发生了。

The conventional wisdom held by many leading physicists --

许多顶尖物理学家所拥有的 传统智慧——

and you've got to stay with me on this one --

这点你们得跟上我——

is that each combination is actually examined by its very own quantum computer

每个组合实际上 是由自己的量子计算机

inside its very own parallel universe.

在自己的平行宇宙中检验的。

Each of these combinations, they add up like waves in a pool of water.

每个组合，它们像波浪一样 积聚在水池中。

错误的那些组合，

The combinations that are wrong,

they cancel each other out.

它们相互抵消掉。

And the combinations that are right,

而那些正确的组合，

they reinforce and amplify each other.

它们加强并相互扩大。

So at the end of the quantum computing program,

所以在量子计算过程结束时，

all that's left is the correct answer,

留下了的就只是 我们可以在这个宇宙中

that we can then observe here in this universe.

看到的正确的答案。

Now, if that doesn't make complete sense to you, don't stress.

如果你没有完全搞懂， 不要紧张。

(Laughter)

（笑声）

You're in good company.

有人陪你们。

Niels Bohr, one of the pioneers of this field,

尼尔斯·波尔， 这个领域的先驱者之一，

he once said that anyone who could contemplate quantum mechanics

他曾经说过任何 认真去思考量子力学

without being profoundly shocked,

而没有被深深震惊到的人，

they haven't understood it.

只是还没有理解它。

(Laughter)

（笑声）

But you get an idea of what we're up against,

但是你们已经知道了 我们要面对的，

and why it's now up to us cryptographers

以及为什么现在我们的密码学家

to really step it up.

要加紧准备应对它。

And we have to do it fast,

而且我们必须行动迅速，

because quantum computers,

因为量子计算机

they already exist in labs all over the world.

已经存在于世界各地的实验室中。

Fortunately, at this minute,

幸运的是，目前，

they only exist at a relatively small scale,

它们仅以相对较小的规模存在，

still too small to break our much larger cryptographic keys.

规模尚无法攻破我们那些 数量庞大的加密密钥。

But we might not be safe for long.

但是我们安全不了太久了。

Some folks believe that secret government agencies

有些人认为秘密政府机构

have already built a big enough one,

已经建立了一个 足够大的量子计算机，

and they just haven't told anyone yet.

只是他们还没有告诉任何人。

Some pundits say they're more like 10 years off.

一些专家说，还有十年时间。

Some people say it's more like 30.

一些人说更有可能是 30 年。

You might think that if quantum computers are 10 years away,

你们可能认为如果我们 距离量子计算机还有十年之远，

我们密码学家肯定还有 足够的时间可以想出办法

surely that's enough time for us cryptographers to figure it out

来及时保护我们的网络。

and to secure the internet in time.

But unfortunately, it's not that easy.

但是不幸的是，没有那么容易。

Even if we ignore the many years that it takes

即使我们忽略进行标准化和部署

to standardize and deploy and then roll out new encryption technology,

所要花费的多年时间， 然后推出新的加密技术，

in some ways we may already be too late.

在某些方面， 我们可能已经来不及了。

Smart digital criminals and government agencies

精明的数字犯罪分子和政府机构

may already be storing our most sensitive encrypted data

可能已经抢在量子计算机 大规模应用之前，

in anticipation for the quantum future ahead.

开始存储我们最敏感的机密数据了。

外国领导人，

The messages of foreign leaders,

of war generals

战争将军，

or of individuals who question power,

或者质疑权力的个人，

they're encrypted for now.

他们的信息现在是加密的。

But as soon as the day comes

但是只要那一天到来，

that someone gets their hands on a quantum computer,

有人有能力操作量子计算机，

they can retroactively break anything from the past.

他们就可以追溯性地 破解过去的一切信息。

在某些政府和金融部门，

In certain government and financial sectors

or in military organizations,

或在军事机构中，

sensitive data has got to remain classified for 25 years.

敏感数据必须保密 25 年。

So if a quantum computer really will exist in 10 years,

所以如果量子计算机 真的在十年后出现，

then these guys are already 15 years too late

那么这些人晚了 15 年，

to quantum-proof their encryption.

已经来不及应对量子危机。

So while many scientists around the world

所以当世界各地的科学家

are racing to try to build a quantum computer,

竞相尝试建造量子计算机时，

us cryptographers are urgently looking to reinvent encryption

我们密码学家正迫切 重塑我们的加密系统，

to protect us long before that day comes.

以在那天到来之前保护我们。

We're looking for new, hard mathematical problems.

我们正在寻找新的数学难题。

We're looking for problems that, just like factorization,

我们正在找 像数字分解那样的难题，

can be used on our smartphones and on our laptops today.

可以用在我们如今的 智能手机和电脑上。

But unlike factorization, we need these problems to be so hard

但是不同于数字分解， 我们需要这个难题足够难，

that they're even unbreakable with a quantum computer.

难到它不能被量子计算机破解。

In recent years, we've been digging around a much wider realm of mathematics

最近几年，我们一直在 探索更广阔的数学领域，

to look for such problems.

来寻找这样的难题。

We've been looking at numbers and objects

我们一直在看那些

比你我习惯所见更加奇特的，

that are far more exotic and far more abstract

比计算器上的那些抽象得多的

than the ones that you and I are used to,

数字和对象。

like the ones on our calculators.

And we believe we've found some geometric problems

而且我们相信我们 已经找到了一些几何问题，

that just might do the trick.

可能会有帮助。

Now, unlike those two- and three-dimensional geometric problems

它不像那些我们 在高中时用图纸和笔

that we used to have to try to solve with pen and graph paper in high school,

解决的二维或三维几何问题，

它们大多数定义在 500 个维度以上。

most of these problems are defined in well over 500 dimensions.

So not only are they a little hard to depict and solve on graph paper,

所以它们不只在草纸上 难以描述和解决，

but we believe they're even out of the reach of a quantum computer.

而且我们相信它们超出了 量子计算机的计算范围。

So though it's early days,

所以虽然现在还早，

it's here that we are putting our hope as we try to secure our digital world

但此时此刻，我们希望 在步入量子未来时，

moving into its quantum future.

可以确保我们数字世界的安全。

Just like all of the other scientists,

就像所有其他的科学家，

we cryptographers are tremendously excited

我们密码学家对于未来 与量子计算机

at the potential of living in a world alongside quantum computers.

一起生活的世界感到非常兴奋。

They could be such a force for good.

这可能是正义的力量。

But no matter what technological future we live in,

但是无论未来 我们有什么样的技术，

our secrets will always be a part of our humanity.

我们的秘密都将一直是 我们人性的一部分，

And that is worth protecting.

而它们值得被保护。

Thanks.

谢谢。

(Applause)

（掌声）