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

Translator: Joseph Geni Reviewer: Camille Martínez

譯者: Lilian Chiu 審譯者: Helen Chang

I'm in the business of safeguarding secrets,

我的工作是保護秘密，

and this includes your secrets.

包括你們的秘密。

Cryptographers are the first line of defense

在一場已經激烈進行了 數世紀的戰爭中，

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

密碼專家是第一道防線：

a war between code makers

加密者和解密者之間的戰爭。

and code breakers.

And this is a war on information.

這是一場資訊戰。

The modern battlefield for information is digital.

現代，資訊的戰場是數位的。

And it wages across your phones,

戰場橫跨你的手機、

your computers

你的電腦，和網路。

and the internet.

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

我們的工作是要設計系統來將 你的電子郵件和信用卡卡號、

你的電話及文字訊息變成亂碼——

your phone calls and text messages --

and that includes those saucy selfies --

也包括那些限制級的自拍——

(Laughter)

（笑聲）

so that all of this information can only be descrambled

我們要讓這些加密資訊

by the recipient that it's intended for.

只能夠被指定的接收者解開。

Now, until very recently,

一直到最近之前，

we thought we'd won this war for good.

我們以為已經永久打贏了這場仗。

Right now, each of your smartphones is using encryption

目前，各位的智慧手機 所用的加密技術

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

是我們認為無法破解， 且會一直無法破解的加密技術。

We were wrong,

我們錯了，

because quantum computers are coming,

因為量子電腦要出現了，

and they're going to change the game completely.

它們會讓局勢完全改觀。

Throughout history, cryptography and code-breaking

在整個歷史上，密碼學和破解密碼 一直在玩貓捉老鼠的遊戲。

has always been this game of cat and mouse.

Back in the 1500s,

十六世紀時，

Queen Mary of the Scots thought she was sending encrypted letters

蘇格蘭的瑪莉一世女王認為 她所發出的加密信件

that only her soldiers could decipher.

只有她的士兵能夠解開。

But Queen Elizabeth of England,

但英格蘭的伊麗莎白 女王的解密者完全勝出。

she had code breakers that were all over it.

They decrypted Mary's letters,

他們破解了瑪莉的信件，

saw that she was attempting to assassinate Elizabeth

發現她打算要刺殺伊麗莎白，

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

後來，他們便砍下了瑪莉一世的頭。

A few centuries later, in World War II,

幾世紀後，在二次大戰期間，

the Nazis communicated using the Engima code,

納粹使用恩尼格瑪密碼來溝通，

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

他們認為這種更複雜的 加密方式是無法破解的。

But then good old Alan Turing,

但，接著，好樣的艾倫圖靈，

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

也就是發明了現代 電腦的那個傢伙，

he built a machine and used it to break Enigma.

他打造了一台機器 來破解恩尼格瑪密碼。

He deciphered the German messages

他破解了德國人的訊息，協助 阻止了希特勒和他的納粹德國。

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

And so the story has gone throughout the centuries.

所以，這個故事 已經進行了數個世紀。

Cryptographers improve their encryption,

密碼學家改進他們的加密方式，

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

接著，破解密碼的人又反擊， 找出方式來破解。

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

這場戰爭你來我往，競爭激烈。

That was until the 1970s,

直到七○年代，

when some cryptographers made a huge breakthrough.

一些密碼學家有了重大的突破。

They discovered an extremely powerful way to do encryption

他們發現了一種 極強大的加密方式，

called "public-key cryptography."

叫做「公開金鑰密碼學」。

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

和過去使用過的所有方法不同，

打算交換機密資訊的雙方 不用事前交換秘密金鑰。

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

have exchanged the secret key beforehand.

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

公開金鑰密碼學的美好之處就在於

它讓我們能夠和世界上 任何一個人進行安全的連結，

with anyone in the world,

whether we've exchanged data before or not,

不論我們以前是否交換過資料，

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

且它的速度超快，快到你我 都還沒意識到之前就已經完工。

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

不論是你傳訊息約好友出來喝酒，

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

或者你是一間銀行， 要轉數十億美金給另一家銀行，

modern encryption enables us to send data that can be secured

現代加密方式讓我們能夠

在幾毫秒的時間內 就完成安全的資料傳輸。

in a matter of milliseconds.

The brilliant idea that makes this magic possible,

讓這種魔法成為可能的聰明想法

it relies on hard mathematical problems.

要仰賴困難的數學問題。

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

密碼學家對於計算機 做不到的事都深感興趣。

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

比如，計算機可以 把任何兩個數字相乘，

no matter how big the size.

不論數字多大。

But going back the other way --

但換個方向——

starting with the product and then asking,

先從乘積開始，接著問：

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

「哪兩個數字相乘會得到 這個乘積？」——

that's actually a really hard problem.

那就是困難的問題。

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

若我請你找出哪兩個數字

相乘會得到 851，

即使有計算機，

even with a calculator,

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

這裡大部分的人也很難 在這場演說結束前解出答案。

by the time I'm finished with this talk.

And if I make the numbers a little larger,

如果我用大一點的數字，

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

地球上就沒有一台 計算機能找出答案來。

In fact, even the world's fastest supercomputer

事實上，就連世界上 最快的超級電腦，

would take longer than the life age of the universe

也要花上比宇宙生命更長的時間

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

才找得出是哪兩個數字 相乘得到這個乘積。

And this problem, called "integer factorization,"

這個問題叫做 「整數的因數分解」，

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

各位現在的智慧手機和筆電

就是使用這個方法 來確保資料的安全性。

to keep your data secure.

This is the basis of modern encryption.

它是現代加密技術的基礎。

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

既然地球上所有的計算能力 結合起來都無法破解它，

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

因此我們密碼學家便認為 我們已經找到方法

to stay ahead of the code breakers for good.

可以永遠領先破解密碼者了。

Perhaps we got a little cocky

也許我們太驕傲了，

because just when we thought the war was won,

因為就在我們自以為 已經打了勝仗時，

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

一群二十世紀的 物理學家加入戰局，

and they revealed that the laws of the universe,

他們點出，宇宙的定律，

the same laws that modern cryptography was built upon,

也就是做為現代密碼學 基礎的那些定律，

they aren't as we thought they were.

它們並非我們所想的那樣。

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

我們認為一個物體不可能 同時出現在兩個地方。

It's not the case.

並非如此。

We thought nothing can possibly spin clockwise and anticlockwise

我們以為沒有任何東西能夠

同時順時鐘又逆時鐘轉動。

simultaneously.

But that's incorrect.

但那並不正確。

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

我們以為在宇宙 相對兩邊的兩個物體，

light years away from each other,

相距數光年之遠，

they can't possibly influence one another instantaneously.

它們就不可能即時影響彼此。

We were wrong again.

我們又錯了。

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

人生似乎總是這樣，不是嗎？

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

就在你以為你什麼 都考慮了也準備好了，

卻出現一票物理學家， 點出宇宙的基本定律

a bunch of physicists come along

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

和你所想的完全不一樣？

這把一切都搞砸了。

to what you thought?

(Laughter)

（笑聲）

And it screws everything up.

See, in the teeny tiny subatomic realm,

在非常微小的次原子領域中，

at the level of electrons and protons,

在電子和光子的層級上，

the classical laws of physics,

我們知道且喜愛的物理標準定律，

the ones that we all know and love,

they go out the window.

都可以丟掉了。

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

這就要談到量子力學的定律了。

In quantum mechanics,

在量子力學中，

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

電子可以同時順時鐘 和逆時鐘轉動，

and a proton can be in two places at once.

光子可以同時位在兩個地方。

It sounds like science fiction,

聽起來很科幻，

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

但那只是因為我們的宇宙 有著很瘋狂的量子特性，

it hides itself from us.

這特性隱藏著沒被我們發現。

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

一直藏到二十世紀才被我們發現。

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

但現在我們知道了， 全世界都加入軍備競賽，

to try to build a quantum computer --

比賽建造量子電腦——

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

量子電腦可以利用 這種怪異量子行為的力量。

These things are so revolutionary

這種電腦非常具有革命性

and so powerful

且非常強大，

that they'll make today's fastest supercomputer

厲害到會讓現今最快的超級電腦

look useless in comparison.

相較之下都變得很沒用。

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

事實上，針對我們 很感興趣的某些問題，

today's fastest supercomputer is closer to an abacus

現今最快的超級電腦還比較 接近算盤，而非量子電腦。

than to a quantum computer.

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

是的，算盤就是那些 有珠子在上頭的木製品。

Quantum computers can simulate chemical and biological processes

量子電腦能模擬化學和生物過程，

that are far beyond the reach of our classical computers.

遠超過我們的標準電腦 能做到的程度。

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

因此，量子電腦保證 能協助我們解決

地球上一些最大的問題。

They're going to help us combat global hunger;

它們可以協助我們對抗全球飢荒，

to tackle climate change;

處理氣候變遷，

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

針對我們目前沒輒的 疾病和流行病找出解藥，

to create superhuman artificial intelligence;

創造出超人類的人工智慧，

and perhaps even more important than all of those things,

還有，可能比上述這些都更重要的是

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

能協助我們了解宇宙的本質。

But with this incredible potential

但，這麼驚人的潛能

comes an incredible risk.

也伴隨著極大的風險。

Remember those big numbers I talked about earlier?

還記得我先前談到的那些大數字嗎？

I'm not talking about 851.

我指的不是 851。

In fact, if anyone in here has been distracted

事實上，如果在座有人分心 去試著找出那些因數，

trying to find those factors,

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

我來幫你從痛苦中解脫， 答案是 23 乘以 37。

(Laughter)

（笑聲）

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

我指的是在 857 之後 更大更大的那個數字。

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

雖然現今最快的超級電腦 花上宇宙一生的時間

in the life age of the universe,

也無法找出那些因數，

a quantum computer could easily factorize numbers

但量子電腦能夠將 比那個數字更大許多的數字

way, way bigger than that one.

輕易拆解成因數。

Quantum computers will break all of the encryption currently used

量子電腦能破解目前用來保護你我

to protect you and I from hackers.

抵禦駭客的所有加密技術。

And they'll do it easily.

且輕輕鬆鬆就能辦到。

Let me put it this way:

讓我這麼說：

if quantum computing was a spear,

如果量子計算是一支長矛，

then modern encryption,

那現代的加密系統，

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

也就是數十年都沒被破解， 一直在保護我們的系統，

it would be like a shield made of tissue paper.

它就像是用衛生紙做的盾牌。

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

任何人只要能夠使用量子電腦， 就等於拿到一把萬能鑰匙，

to unlock anything they like in our digital world.

在數位世界，他們想要 解鎖什麼就能解鎖什麼。

They could steal money from banks

他們能從銀行偷錢，

and control economies.

控制經濟，

They could power off hospitals or launch nukes.

能讓醫院斷電或者發射核彈，

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

還可以只是坐著，透過網路攝影機

without any of us knowing that this is happening.

監視我們，不會被我們知道。

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

在我們現在所使用的電腦上，

像這台電腦上，資訊的基礎單位

like this one,

it's called a "bit."

叫做「位元」。

A single bit can be one of two states:

單一個位元可能有兩種狀態：

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

它可能是零或一。

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

我媽在世界的另一端， 當我和她視訊通話時，

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

她看到這張投影片一定會殺了我——

(Laughter)

（笑聲）

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

我們其實只是發送一串 又一串的零和一給彼此，

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

它們會在電腦及衛星間彈來彈去，

transmitting our data at a rapid pace.

快速傳輸我們的資料。

Bits are certainly very useful.

位元非常有用，無庸置疑。

In fact, anything we currently do with technology

事實上，我們目前 用科技所做的任何事，

is indebted to the usefulness of bits.

都受惠於這些好用的位元。

But we're starting to realize

但，我們開始了解到位元很不擅長

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

模擬複雜的分子和粒子。

And this is because, in some sense,

原因是因為，在某種意義上，

subatomic processes can be doing two or more opposing things

次原子過程可以同時進行 兩件以上相反的事情，

at the same time

as they follow these bizarre rules of quantum mechanics.

因為它們遵循的是 這些怪異的量子力學規則。

So, late last century,

所以，上個世紀末，

some really brainy physicists had this ingenious idea:

一些非常聰明的物理學家 想出了一個天才點子：

to instead build computers that are founded

改用量子力學的原則來建造電腦。

on the principles of quantum mechanics.

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

在量子電腦上，資訊的基礎單位

it's called a "qubit."

叫做「量子位」。

It stands for "quantum bit."

是「量子位元」的簡稱。

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

量子位不只有零和一兩個狀態，

a qubit can be an infinite number of states.

它可以有無限多個狀態。

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

因為它可以同時是零和一的組合，

at the same time,

a phenomenon that we call "superposition."

這種現象被我們稱為「疊加」。

And when we have two qubits in superposition,

當有兩個量子位疊加時，

we're actually working across all four combinations

我們其實是在處理全部四種組合：

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

零和零、零和一、 一和零、一和一。

With three qubits,

有三個量子位時，

we're working in superposition across eight combinations,

我們就有八種組合的疊加，

and so on.

以此類推。

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

每當我們增加一個量子位，

我們同時能用的

that we can work with in superposition

疊加組合數目就會加倍。

at the same time.

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

所以，當我們擴大規模， 使用許多量子位時，

we can work with an exponential number of combinations

我們同時能夠用的組合數目

會是指數增加。

at the same time.

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

從這點就可以略知 量子電腦的能力從何而來。

Now, in modern encryption,

在現代的加密技術中，

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

我們的秘密金鑰，比如 那個大數字的兩個因數，

they're just long sequences of zeroes and ones.

它們都是長串的零和一。

To find them,

要找出它們，標準的電腦

a classical computer must go through every single combination,

必須把所有可能組合 一組一組試過，

one after the other,

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

直到找到行得通的組合， 就破解了我們的加密。

But on a quantum computer,

但在量子電腦上，

with enough qubits in superposition,

只要有足夠的疊加量子位，

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

就可以同時從 所有組合來擷取資訊。

In very few steps,

只要少數幾個步驟，

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

量子電腦就能把所有 不正確的組合排除，

home in on the correct one

鎖定正確的組合，

and then unlock our treasured secrets.

接著揭露我們寶貴的秘密。

Now, at the crazy quantum level,

在瘋狂的量子層級上，

something truly incredible is happening here.

發生的現象非常不可思議。

The conventional wisdom held by many leading physicists --

許多頂尖物理學家 所擁有的傳統知識是——

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

你們要專心聽我說，別分神——

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

每種組合其實是 在它自己的平行宇宙中，

由它自己的量子電腦來檢查。

inside its very own parallel universe.

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

每個組合加在一起， 就像一池水中的水波。

The combinations that are wrong,

錯誤的組合

they cancel each other out.

會彼此抵消。

And the combinations that are right,

正確的組合

they reinforce and amplify each other.

會強化、放大彼此。

So at the end of the quantum computing program,

所以，在量子計算程式結束時，

all that's left is the correct answer,

留下來的就只有正確答案，

that we can then observe here in this universe.

我們在這個宇宙中 就可以觀察到這個答案。

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

如果你覺得還無法 完全理解，別擔心。

(Laughter)

（笑聲）

You're in good company.

你不孤單。

Niels Bohr, one of the pioneers of this field,

尼爾斯 · 波耳是 這個領域的先鋒之一，

he once said that anyone who could contemplate quantum mechanics

他曾經說過，如果有人 在深入思考量子力學時

without being profoundly shocked,

沒被深深驚嚇到，

they haven't understood it.

那他就還沒搞懂量子力學。

(Laughter)

（笑聲）

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

但你們多少了解了我們在對抗什麼，

and why it's now up to us cryptographers

及為什麼現在要靠 我們密碼學家來加把勁了。

to really step it up.

And we have to do it fast,

且我們的動作要快，

because quantum computers,

因為量子電腦

they already exist in labs all over the world.

已經存在於世界各地的實驗室中。

Fortunately, at this minute,

幸運的是，此刻，

they only exist at a relatively small scale,

它們相對還算小規模的電腦，

still too small to break our much larger cryptographic keys.

還太小到無法破解 我們更大的密碼學金鑰。

But we might not be safe for long.

但安全的日子可能不長了。

Some folks believe that secret government agencies

有些人相信，政府有些秘密機構 已經建立出了夠大的量子電腦，

have already built a big enough one,

and they just haven't told anyone yet.

只是還沒有告訴任何人。

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

有些行家說大概還有十年的距離。

Some people say it's more like 30.

有些人說比較可能是三十年。

你們可能想，倘若 量子電腦十年後才會出現，

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

我們密碼學家當然有足夠的時間 想辦法及時保護網路的安全。

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

and to secure the internet in time.

But unfortunately, it's not that easy.

但，不幸的是，沒那麼簡單。

Even if we ignore the many years that it takes

即使我們忽略 還要花許多年的時間

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

才能將一項新的加密技術 標準化、部署、再推出，

in some ways we may already be too late.

在某些層面上我們已經太遲了。

Smart digital criminals and government agencies

聰明的數位罪犯和政府機構

may already be storing our most sensitive encrypted data

可能因為預期將來會是量子的未來，

in anticipation for the quantum future ahead.

而已經在儲存我們 最敏感的加密資料。

The messages of foreign leaders,

來自外國領袖、

of war generals

戰爭指揮官

or of individuals who question power,

或執疑當權者的人的訊息

they're encrypted for now.

目前有加密。

But as soon as the day comes

但隨時間過去，

that someone gets their hands on a quantum computer,

有人取得了量子電腦，

they can retroactively break anything from the past.

就能追溯回去，破解 過去的任何加密資訊。

In certain government and financial sectors

在某些政府和財務部門 或在軍事組織中，

or in military organizations,

sensitive data has got to remain classified for 25 years.

敏感的資料被列為 二十五年之久的機密。

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

如果十年後真的會出現量子電腦，

then these guys are already 15 years too late

那麼，這些人也遲了十五年 才開始想把加密做到能對付量子，

to quantum-proof their encryption.

So while many scientists around the world

雖然全世界許多科學家

are racing to try to build a quantum computer,

在比賽誰先建造出量子電腦，

us cryptographers are urgently looking to reinvent encryption

我們密碼學家則是急著 想辦法重新發明加密技術，

to protect us long before that day comes.

在那天到來之前就先保護好我們。

We're looking for new, hard mathematical problems.

我們在尋找新的、困難的數學問題。

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

我們在尋找類似 因數拆解這樣的問題，

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

可以用在我們現今的 智慧手機和筆電上。

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

但，我們需要的問題 遠比因數拆解更困難，

that they're even unbreakable with a quantum computer.

難到用量子電腦也無法破解。

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

這幾年，我們在 更廣泛的數學領域中

to look for such problems.

試圖找到這樣的問題。

We've been looking at numbers and objects

我們在研究的那些數字和物體 奇特、抽象的程度遠超過

that are far more exotic and far more abstract

你我習慣的那些， 比如我們計算機上的那些。

than the ones that you and I are used to,

like the ones on our calculators.

And we believe we've found some geometric problems

我們相信，我們已經找到了 一些可能可以用的幾何問題。

that just might do the trick.

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

不像我們在高中時用筆和座標紙

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

就能解開的二維、三維幾何問題，

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

我們找的問題大部分都定義在 至少五百維的空間上。

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

因此不僅難以畫座標紙 來解出這些問題，

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

我們相信連量子電腦也拿它們沒輒。

So though it's early days,

所以，雖然現在還在初期， 我們把希望放在這裡，

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

在我們的數位世界邁向量子未來 之際，努力讓它還能保有安全性。

moving into its quantum future.

Just like all of the other scientists,

和所有其他科學家一樣，

we cryptographers are tremendously excited

我們密碼學家對於 有可能見到量子電腦

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

出現在我們的世界上， 感到非常興奮。

They could be such a force for good.

它們可能成為強大的正義力量。

But no matter what technological future we live in,

但，不論我們的科技未來 是什麼樣子的，

our secrets will always be a part of our humanity.

我們的秘密將永遠是人類的一部分。

And that is worth protecting.

那是值得去保護的。

Thanks.

謝謝。

(Applause)

（掌聲）