听力课堂TED音频栏目主要包括TED演讲的音频MP3及中英双语文稿，供各位英语爱好者学习使用。本文主要内容为演讲MP3+双语文稿:在信息战中，量子计算机会击败密码学家吗?，希望你会喜欢！
【演讲人及介绍】Craig Costello
出版商，密码学家克雷格·科斯特洛（Craig Costello）使用数学方法来保护数字世界，以抵御当前存在的威胁和未来可能存在的威胁。
【演讲主题】在信息战争中，量子计算机会击败密码学家吗?
【演讲文稿-中英文】
翻译者 Nan Yang 校对 Jiasi Hao
00:12
I'm in the business of safeguardingsecrets, and this includes your secrets.
我从事保护秘密的工作，其中就包括你们的秘密。
00:19
Cryptographers are the first line ofdefense in an ongoing war that's been raging for centuries: a war between codemakers and code breakers. And this is a war on information. The modernbattlefield for information is digital. And it wages across your phones, yourcomputers and the internet. Our job is to create systems that scramble youremails and credit card numbers, your phone calls and text messages -- and thatincludes those saucy selfies --
密码学家是数百年来持续不断的战争中的第一道防线：是代码编写者和代码破译者之间的战争。这是一场信息战争。现代信息战场是数字化的。它发动于你的手机，你的电脑和互联网。我们的工作是建立系统，来打乱你们的电子邮件内容，信用卡号，电话内容和短信——这包括那些搞笑的自拍照——
00:50
(Laughter)
（笑声）
00:52
so that all of this information can only bedescrambled by the recipient that it's intended for.
这样，所有的这些信息只能由预期的接收者解密。
00:58
Now, until very recently, we thought we'dwon this war for good. Right now, each of your smartphones is using encryptionthat we thought was unbreakable and that was going to remain that way. We werewrong, because quantum computers are coming, and they're going to change thegame completely.
一直以来，我们都一直以为自己永远赢得了这场战争。现在，你们每个人的手机都在使用我们认为永远无法被破解的加密手段，我们错了，因为量子计算机即将加入这场战争，它们会彻底改变游戏规则。
01:20
Throughout history, cryptography andcode-breaking has always been this game of cat and mouse. Back in the 1500s,Queen Mary of the Scots thought she was sending encrypted letters that only hersoldiers could decipher. But Queen Elizabeth of England, she had code breakersthat were all over it. They decrypted Mary's letters, saw that she wasattempting to assassinate Elizabeth and, subsequently, they chopped Mary's headoff. A few centuries later, in World War II, the Nazis communicated using theEngima code, a much more complicated encryption scheme that they thought wasunbreakable. But then good old Alan Turing, the same guy who invented what wenow call the modern computer, he built a machine and used it to break Enigma.He deciphered the German messages and helped to bring Hitler and his ThirdReich to a halt. And so the story has gone throughout the centuries.Cryptographers improve their encryption, and then code breakers fight back andthey find a way to break it. This war's gone back and forth, and it's beenpretty neck and neck.
纵观历史，密码学和密码破解一直是猫和老鼠的游戏。回到十五世纪，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。但是英格兰的伊丽莎白女王手下有无数的密码破译者。他们破解了玛丽的信件，发现了她正试图刺杀伊丽莎白，随后，他们砍掉了玛丽的头。几个世纪之后的第二次世界大战，Nazi使用恩尼格玛密码进行通讯，是一种他们认为牢不可破的更复杂的加密机制。但是之后的艾伦·图灵，那个发明了我们称为现代计算机的人，制作了一个机器，用它来破解恩尼格玛。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。这种故事已经重复了多个世纪。密码学家不断改善他们的加密方式，然后密码破译者进行反击，找到一种方法来破解它。这场战争来来回回，而且双方差不多并驾齐驱。
02:25
That was until the 1970s, when somecryptographers made a huge breakthrough. They discovered an extremely powerfulway to do encryption called "public-key cryptography." Unlike all ofthe prior methods used throughout history, it doesn't require that the twoparties that want to send each other confidential information have exchangedthe secret key beforehand. The magic of public-key cryptography is that itallows us to connect securely with anyone in the world, whether we've exchangeddata before or not, and to do it so fast that you and I don't even realize it'shappening. Whether you're texting your mate to catch up for a beer, or you're abank that's transferring billions of dollars to another bank, modern encryptionenables us to send data that can be secured in a matter of milliseconds.
直到 19 世纪 70 年代，一些密码学家取得了巨大的突破。他们发现了一种非常强大的加密方式，叫做“公钥密码学”。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提前交换密钥。公钥密码学的魔力在于，它允许我们安全地与世界上任何人连接起来，无论我们事先交换过数据与否，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，还是你正在转账数十亿美元到另一家银行，现代加密技术使我们能够在几毫秒内发送被保护的数据。
03:17
The brilliant idea that makes this magicpossible, it relies on hard mathematical problems. Cryptographers are deeplyinterested in things that calculators can't do. For example, calculators canmultiply any two numbers you like, no matter how big the size. But going backthe other way -- starting with the product and then asking, "Which twonumbers multiply to give this one?" -- that's actually a really hardproblem. If I asked you to find which two-digit numbers multiply to give 851,even with a calculator, most people in this room would have a hard time findingthe answer by the time I'm finished with this talk. And if I make the numbers alittle larger, then there's no calculator on earth that can do this.And thisproblem, called "integer factorization," is exactly what each of yoursmartphones and laptops is using right now to keep your data secure. This isthe basis of modern encryption. And the fact that all the computing power onthe planet combined can't solve it, that's the reason we cryptographers thoughtwe'd found a way to stay ahead of the code breakers for good.
使这个魔法成为可能的绝妙主意，依赖于困难的数学问题。密码学家对计算器无法做到的事情深感兴趣。例如，计算器可以让你喜欢的任何两个数字相乘，无论数字有多大。但是反过来——有相乘后的结果，然后问“哪两个数字相乘得出的这个数字？”这实际上是个非常难的问题。如果我让你找出哪两个两位数相乘等于 851，即使有计算器，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。而且如果我让数字变得更大些，地球上没有任何计算器可以做到。而这个问题，被叫做“整数分解”，就是现在你们每部手机和电脑正在用来保护你们的数据安全的方法。这是现代加密的基础。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。
04:37
Perhaps we got a little cocky because justwhen we thought the war was won, a bunch of 20th-century physicists came to theparty, and they revealed that the laws of the universe, the same laws thatmodern cryptography was built upon, they aren't as we thought they were. Wethought that one object couldn't be in two places at the same time. It's notthe case. We thought nothing can possibly spin clockwise and anticlockwisesimultaneously. But that's incorrect. And we thought that two objects onopposite sides of the universe, light years away from each other, they can'tpossibly influence one another instantaneously. We were wrong again.
也许我们有点自大，因为就在我们以为战争胜利的时候，一批 20 世纪的物理学家也加入了进来，他们揭示了宇宙的定律并不是我们想象的那样，而现代密码学的建立就基于这些定律。我们认为一个物体不能同时处于两个地方。事实并非如此。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。但这也不是正确的。我们认为分别位于宇宙两侧的两个物体彼此相距若干光年，它们不可能瞬间相互影响。我们又错了。
05:20
And isn't that always the way life seems togo? Just when you think you've got everything covered, your ducks in a row, abunch of physicists come along and reveal that the fundamental laws of theuniverse are completely different to what you thought?
生活也总是这样，不是吗？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，并揭示了宇宙的基本定律与你想的完全不同？
05:32
(Laughter)
（笑声）
05:33
And it screws everything up.
它搞砸了一切。
05:35
See, in the teeny tiny subatomic realm, atthe level of electrons and protons, the classical laws of physics, the onesthat we all know and love, they go out the window. And it's here that the lawsof quantum mechanics kick in. In quantum mechanics, an electron can be spinningclockwise and anticlockwise at the same time, and a proton can be in two placesat once. It sounds like science fiction, but that's only because the crazyquantum nature of our universe, it hides itself from us. And it stayed hiddenfrom us until the 20th century. But now that we've seen it, the whole world isin an arms race to try to build a quantum computer -- a computer that canharness the power of this weird and wacky quantum behavior.
结果就是，在微小的亚原子领域，在电子和质子的级别上，我们都熟知和热爱的物理的经典定律，不复存在。而量子力学定律就在这里展开。在量子力学中，电子可以同时进行顺时针和逆时针旋转，而一个质子可以同时处于两个位置。这听起来像科幻小说，但是这仅仅是因为宇宙的疯狂量子本质，对我们隐藏了自己，直到 20 世纪。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——一种能够利用古怪的量子行为力量的计算机。
06:28
These things are so revolutionary and sopowerful that they'll make today's fastest supercomputer look useless incomparison. In fact, for certain problems that are of great interest to us,today's fastest supercomputer is closer to an abacus than to a quantumcomputer. That's right, I'm talking about those little wooden things with thebeads. Quantum computers can simulate chemical and biological processes thatare far beyond the reach of our classical computers. And as such, they promiseto help us solve some of our planet's biggest problems. They're going to helpus combat global hunger; to tackle climate change; to find cures for diseasesand pandemics for which we've so far been unsuccessful; to create superhumanartificial intelligence; and perhaps even more important than all of thosethings, they're going to help us understand the very nature of our universe.
这些东西太具有颠覆性了，而且如此强大，会使得现在最快的超级计算机相比之下看起来毫无用处。实际上，对于我们非常感兴趣的某些问题，如今最快的超级电脑更接近于一个算盘，而不是量子计算机。是的，我说的就是那种带有珠子的小小的木制品。量子计算机可以模拟化学和生物过程，这远远超出了传统计算机的范围。因此，它们很可能会帮助我们解决地球上一些最大的问题。他们将帮助我们战胜全球饥饿；应对气候变化，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，创造超人类的人工智能，以及比所有这些事情都重要的，它将帮助我们理解宇宙的本质。
07:28
But with this incredible potential comes anincredible risk. Remember those big numbers I talked about earlier? I'm nottalking about 851. In fact, if anyone in here has been distracted trying tofind those factors, I'm going to put you out of your misery and tell you thatit's 23 times 37.
但是伴随着不可思议的潜力，也带来了不可思议的风险。还记得我之前说过的大数字吗？我现在说的不是 851。实际上，如果你们任何人因为要找到这些因数而分心，我要把你从苦难中解救出来，告诉你答案是 23 乘 37 。
07:47
(Laughter)
（笑声）
07:48
I'm talking about the much bigger numberthat followed it. While today's fastest supercomputer couldn't find those factorsin the life age of the universe, a quantum computer could easily factorizenumbers way, way bigger than that one.
我要说的是比那大得多的数字。虽然当今最快的超级计算机无法在宇宙生命周期中找到那些因数，但一个量子计算机可以轻易的分解比那大很多很多的数字。
08:03
Quantum computers will break all of theencryption currently used to protect you and I from hackers. And they'll do iteasily. Let me put it this way: if quantum computing was a spear, then modernencryption, the same unbreakable system that's protected us for decades, itwould be like a shield made of tissue paper. Anyone with access to a quantumcomputer will have the master key to unlock anything they like in our digitalworld. They could steal money from banks and control economies. They couldpower off hospitals or launch nukes. Or they could just sit back and watch allof us on our webcams without any of us knowing that this is happening.
量子计算机将打破我们现在用来保护大家免受黑客攻击的所有加密算法。它们会轻松做到的。让我这样说吧：如果量子计算是一根长矛，那么现代加密——几十年来一直保护着我们的牢不可破的系统，就像是纸巾做的盾牌。有权访问量子计算机的任何人都将拥有万能钥匙，可以解锁他们在数字化世界中喜欢的任何东西。他们可以从银行偷钱，并控制经济，他们可以关闭医院电源，或者发射核武器，或者他们可以只是坐下来，通过网络摄像头看着我们，而我们没有人知道发生了什么。
08:49
Now, the fundamental unit of information onall of the computers we're used to, it's called a "bit." A single bitcan be one of two states: it can be a zero or it can be a one. When I FaceTimemy mum from the other side of the world --
我们习惯使用的所有计算机上的基本信息单元，叫做一个“比特”。一个比特可以处于两个状态之一：它可以是 0 或者 1。当我和地球另一端的妈妈视频的时候——
09:09
we're actually just sending each other longsequences of zeroes and ones that bounce from computer to computer, fromsatellite to satellite, transmitting our data at a rapid pace. Bits arecertainly very useful. In fact, anything we currently do with technology isindebted to the usefulness of bits. But we're starting to realize that bits arereally poor at simulating complex molecules and particles. And this is because,in some sense, subatomic processes can be doing two or more opposing things atthe same time as they follow these bizarre rules of quantum mechanics.
我们实际上只是在给彼此发送一长串的 0 和 1，在计算机之间，卫星之间反复，高速地传输着我们的数据。比特当然非常有用。实际上，我们现在技术上做的任何事情都多亏了比特。但是我们开始意识到，在模拟复杂的分子和粒子方面，比特做得很差。这是因为，在某种意义上，亚原子过程可以同时做两个或更多相反的事情，因为他们遵循量子力学的这些怪异规则。
09:43
So, late last century, some really brainyphysicists had this ingenious idea: to instead build computers that are foundedon the principles of quantum mechanics. Now, the fundamental unit of informationof a quantum computer, it's called a "qubit." It stands for"quantum bit." Instead of having just two states, like zero or one, aqubit can be an infinite number of states. And this corresponds to it beingsome combination of both zero and one at the same time, a phenomenon that wecall "superposition." And when we have two qubits in superposition,we're actually working across all four combinations of zero-zero, zero-one,one-zero and one-one. With three qubits, we're working in superposition acrosseight combinations, and so on. Each time we add a single qubit, we double thenumber of combinations that we can work with in superposition at the same time.And so when we scale up to work with many qubits, we can work with anexponential number of combinations at the same time. And this just hints atwhere the power of quantum computing is coming from.
所以，上个世纪后期，一些非常聪明的物理学家有了这个巧妙的想法：建立基于量子力学原理的计算机。量子计算机的基本信息单位叫做一个“量子比特”（qubit），是“quantum bit”的缩写。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。这对应于它同时是 0 和 1 的某种组合，我们称这种现象为“叠加”。当我们有两个量子比特叠加在一起时，实际上，我们正在研究四种组合，0 - 0 ，0 - 1 ，1 - 0 ，和 1 - 1。有三个量子比特时，我们在研究八种组合的叠加状态，以此类推。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将加倍。所以当我们扩大规模，处理很多量子比特时，我们需要同时处理的组合状态数量呈指数型增加。而这就暗示了量子计算的力量从何而来。
10:56
Now, in modern encryption, our secret keys,like the two factors of that larger number, they're just long sequences ofzeroes and ones. To find them, a classical computer must go through everysingle combination, one after the other, until it finds the one that works andbreaks our encryption. But on a quantum computer, with enough qubits insuperposition, information can be extracted from all combinations at the sametime. In very few steps, a quantum computer can brush aside all of theincorrect combinations, home in on the correct one and then unlock ourtreasured secrets.
如今，在现代加密中，我们的密钥，例如大数的分解因子，它们只是 0 和 1 的长序列。为了找到它们，一个传统计算机必须实验所有的组合可能，一个接着一个，直到找到那对可以成功破译加密的组合。但是在量子计算机中，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。只需几个步骤，一个量子计算机就可以撇开所有不正确的组合，留住正确的那个，然后解锁我们珍贵的秘密。
11:44
Now, at the crazy quantum level, somethingtruly incredible is happening here. The conventional wisdom held by manyleading physicists -- and you've got to stay with me on this one -- is thateach combination is actually examined by its very own quantum computer insideits very own parallel universe. Each of these combinations, they add up likewaves in a pool of water. The combinations that are wrong, they cancel eachother out. And the combinations that are right, they reinforce and amplify eachother. So at the end of the quantum computing program, all that's left is thecorrect answer, that we can then observe here in this universe.
在疯狂的量子级别，着实令人难以置信的事情发生了。许多顶尖物理学家所拥有的传统智慧—— 这点你们得跟上我—— 每个组合实际上 是由自己的量子计算机 在自己的平行宇宙中检验的。每个组合，它们像波浪一样 积聚在水池中。错误的那些组合，它们相互抵消掉。而那些正确的组合，它们加强并相互扩大。所以在量子计算过程结束时，留下了的就只是我们可以在这个宇宙中看到的正确的答案。
12:29
Now, if that doesn't make complete sense toyou, don't stress.
如果你没有完全搞懂，不要紧张。
12:32
(Laughter)
（笑声）
12:33
You're in good company. Niels Bohr, one ofthe pioneers of this field, he once said that anyone who could contemplatequantum mechanics without being profoundly shocked, they haven't understood it.
有人陪你们。尼尔斯·波尔，这个领域的先驱者之一，他曾经说过任何认真去思考量子力学而没有被深深震惊到的人，只是还没有理解它。
12:46
(Laughter)
（笑声）
12:47
But you get an idea of what we're upagainst, and why it's now up to us cryptographers to really step it up. And wehave to do it fast, because quantum computers, they already exist in labs allover the world.
但是你们已经知道了我们要面对的，以及为什么现在我们的密码学家要加紧准备应对它。而且我们必须行动迅速，因为量子计算机已经存在于世界各地的实验室中。
13:03
Fortunately, at this minute, they onlyexist at a relatively small scale, still too small to break our much largercryptographic keys. But we might not be safe for long. Some folks believe thatsecret government agencies have already built a big enough one, and they justhaven't told anyone yet. Some pundits say they're more like 10 years off. Somepeople say it's more like 30. You might think that if quantum computers are 10years away, surely that's enough time for us cryptographers to figure it outand to secure the internet in time.
幸运的是，目前，它们仅以相对较小的规模存在，规模尚无法攻破我们那些数量庞大的加密密钥。但是我们安全不了太久了。有些人认为秘密政府机构已经建立了一个 足够大的量子计算机，只是他们还没有告诉任何人。一些专家说，还有十年时间。一些人说更有可能是 30 年。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来及时保护我们的网络。
13:34
But unfortunately, it's not that easy. Evenif we ignore the many years that it takes to standardize and deploy and thenroll out new encryption technology, in some ways we may already be too late.Smart digital criminals and government agencies may already be storing our mostsensitive encrypted data in anticipation for the quantum future ahead. Themessages of foreign leaders, of war generals or of individuals who questionpower, they're encrypted for now. But as soon as the day comes that someonegets their hands on a quantum computer, they can retroactively break anythingfrom the past. In certain government and financial sectors or in militaryorganizations, sensitive data has got to remain classified for 25 years. So ifa quantum computer really will exist in 10 years, then these guys are already15 years too late to quantum-proof their encryption.
但是不幸的是，没有那么容易。即使我们忽略进行标准化和部署所要花费的多年时间，然后推出新的加密技术，在某些方面，我们可能已经来不及了。精明的数字犯罪分子和政府机构可能已经抢在量子计算机大规模应用之前，开始存储我们最敏感的机密数据了。外国领导人，战争将军，或者质疑权力的个人，他们的信息现在是加密的。但是只要那一天到来，有人有能力操作量子计算机，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，或在军事机构中，敏感数据必须保密 25 年。所以如果量子计算机真的在十年后出现，那么这些人晚了 15 年，已经来不及应对量子危机。
14:34
So while many scientists around the worldare racing to try to build a quantum computer, us cryptographers are urgentlylooking to reinvent encryption to protect us long before that day comes. We'relooking for new, hard mathematical problems. We're looking for problems that,just like factorization, can be used on our smartphones and on our laptopstoday. But unlike factorization, we need these problems to be so hard thatthey're even unbreakable with a quantum computer.
所以当世界各地的科学家竞相尝试建造量子计算机时，我们密码学家正迫切重塑我们的加密系统，以在那天到来之前保护我们。我们正在寻找新的数学难题。我们正在找像数字分解那样的难题，可以用在我们如今的智能手机和电脑上。但是不同于数字分解，我们需要这个难题足够难，难到它不能被量子计算机破解。
15:06
In recent years, we've been digging arounda much wider realm of mathematics to look for such problems. We've been lookingat numbers and objects that are far more exotic and far more abstract than theones that you and I are used to, like the ones on our calculators. And webelieve we've found some geometric problems that just might do the trick. Now,unlike those two- and three-dimensional geometric problems that we used to haveto try to solve with pen and graph paper in high school, most of these problemsare defined in well over 500 dimensions. So not only are they a little hard todepict and solve on graph paper, but we believe they're even out of the reachof a quantum computer. So though it's early days, it's here that we are puttingour hope as we try to secure our digital world moving into its quantum future.
最近几年，我们一直在探索更广阔的数学领域，来寻找这样的难题。我们一直在看那些比你我习惯所见更加奇特的，比计算器上的那些抽象得多的数字和对象。而且我们相信我们已经找到了一些几何问题，可能会有帮助。它不像那些我们在高中时用图纸和笔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。所以它们不只在草纸上难以描述和解决，而且我们相信它们超出了量子计算机的计算范围。所以虽然现在还早，但此时此刻，我们希望在步入量子未来时，可以确保我们数字世界的安全。
15:55
Just like all of the other scientists, wecryptographers are tremendously excited at the potential of living in a worldalongside quantum computers. They could be such a force for good. But no matterwhat technological future we live in, our secrets will always be a part of our humanity.And that is worth protecting.
就像所有其他的科学家，我们密码学家对于未来与量子计算机 一起生活的世界感到非常兴奋。这可能是正义的力量。但是无论未来我们有什么样的技术，我们的秘密都将一直是我们人性的一部分，而它们值得被保护。
16:25
Thanks.
谢谢。
16:26
(Applause)
（掌声）
