Eavesdropping on secret communications is aboutto get harder

　　現在想竊聽秘密聯系會越來越難

　　CRYPTOGRAPHY is an arms race between Alice and Bob, and Eve.

　　艾莉斯，鮑伯和伊芙之間正在進行一場密碼術的軍備競賽。

　　These are the names cryptographers give to two people who are trying to communicateprivily, and to a third who is trying to intercept and decrypt their conversation.

　　這里所說的艾莉斯，鮑伯和伊芙是譯解密碼者的代號，前兩位在努力進行秘密聯系，而第三位伊芙則試圖阻止他們的聯系，并且在盡力破解他們的聯系密碼，希望能夠知道聯系的具體內容。

　　Currently, Alice and Bob are aheadjust.

　　目前，艾莉斯和鮑伯只是暫時領先，

　　But Eve is catching up.

　　但是伊芙正在迎頭趕上。

　　Alice and Bob are therefore lookingfor a whole new way of keeping things secret.

　　因此，艾莉斯和鮑伯正在尋找另一種全新的聯系方式，以保證他們聯系的秘密性。

　　And they may soon have one, courtesy of quantum mechanics.

　　借助于量子力學，他們可能很快就會找到。

　　At the moment cryptography concentrates on making the decrypting part as hard as possible.

　　眼下，密碼系統正集中力量讓解密部分盡可能地難以實施。

　　The industry standard, known as RSA , relies on two keys, one public and one private.

　　被稱為RSA的行業標準，取決于兩種密鑰，一種是公開密鑰，另一種是秘密密鑰。

　　These keys are very big numbers, each of which is derived from the product of the sametwo prime numbers.

　　這此密鑰都是非常龐大的數字，每一個都來源于兩個相同素數的乘積。

　　Anyone can encrypt a message using the public key, but only someone with the private keycan decrypt it.

　　任何人都可以使用公開密鑰加密消息，但只有擁有秘密密鑰的人才能解密。

　　To find the private key, you have to work out what the primes are from the public key.

　　為了找到這個秘密密鑰，人們不得不進行大量的運算，從公開密鑰中找到這兩個素數。

　　Make the primes big enoughand hunting big primes is something of a sport amongmathematiciansand the task of factorising the public key to reveal the primes, thoughpossible in theory, would take too long in practice.

　　雖然，從理論上講，1、要保證素數足夠大發現大的素數是數學家們熱衷的一種游戲，2、對公開密鑰進行因式分解希望找到這些素數，這兩項任務是可能的，但是在實際中將會花費很長時間。

　　Since the 1970s, though, the computers that do the factorisation have got bigger and faster.

　　但是，從二十世紀七十年代以來，能夠進行因式分解的電腦越來越大，速度越來越快。

　　Some cryptographers therefore fear for the future of RSA.

　　一些密碼破譯者因此開始擔心RSA的未來。

　　Hence the interest in quantum cryptography.

　　因此，他們把眼光放到了量子密碼術上。

　　Alice, Bob and Werner, too?

　　艾莉斯，鮑伯，沃莫也這樣嗎?

　　The most developed form of quantum cryptography, known as quantum key distribution,relies on stopping interception, rather than preventing decryption.

　　量子密鑰分配是量子密碼學最流行的方式，它主要是依靠阻止攔截，而不是防止解密上。

　　Once again, the key is a huge numberone with hundreds of digits, if expressed in thedecimal system.

　　這個系統的密鑰還是一個龐大的數字如果以十進制表示的話，一個就有幾百個數字。

　　Alice sends this to Bob as a series of photons before she sends the encrypted message.

　　艾莉斯在發送加密信息之前，會先發送一系列的光量子給鮑伯。

　　For Eve to read this transmission, and thus obtain the key, she must destroy some photons.

　　因為伊芙要想讀到這個信息，從而獲得密鑰，她必須要破壞一些光量子。

　　Since Bob will certainly notice the missing photons, Eve will need to create and sendidentical ones to Bob to avoid detection.

　　因為鮑伯肯定會注意到這些消失的光子，伊芙就必須創造并向鮑伯發送相同的光子，才能不會被發覺。

　　But Alice and Bob can stop that by using two different quantum properties, such as thepolarities of the photons, to encode the ones and zeros of which the key is composed.

　　但是艾莉斯和鮑伯通過將兩種不同屬性比如不同極性的光子--的量子轉譯成1和0，以阻止伊芙的攔截。

　　According to Werner Heisenberg s Uncertainty Principle, only one of these two properties canbe measured, so Eve cannot reconstruct each photon without making errors.

　　根據海森堡的不確定性原理，伊芙只能捕捉到這兩種不同屬性光子中的一種，所以她無法完全再造出一模一樣的光子。

　　If Bob detects such errors he can tell Alice not to send the actual message until the line hasbeen secured.

　　如果鮑伯發現這種錯誤的話，他就會通知艾莉斯，在通信渠道安全之前，不要發送真正的信息。

　　One exponent of this approach is ID Quantique, a Swiss firm.

　　運用這種編碼方式的典型代表是一家叫ID Quantique的瑞士公司。

　　In collaboration with Battelle, an American one, it is building a 700km fibre-optic QKD linkbetween Battelle s headquarters in Columbus, Ohio, and the firm s facilities in and aroundWashington, DC.

　　在與一家名稱巴特爾的美國公司合作過程中，該公司在巴特爾位于俄亥俄州哥倫布市的總部，和該公司在華盛頓特區附近及市區的工廠之間，建立了一條700公里的光纖量子密碼的鏈接。

　　Battelle will use this to protect its own information and the link will also be hired to otherfirms that want to move sensitive data around.

　　巴特爾將使用這個光子鏈接來保護它的自身信息，同時這個鏈接也會在其它打算頻繁交換信息的公司中使用。

　　QuintessenceLabs, an Australian firm, has a different approach to encoding.

　　一家名叫QuintessenceLabs的澳大利亞公司的編碼方式卻不一樣。

　　Instead of tinkering with photons polarities, it changes their phases and amplitudes.

　　這家公司并沒有在光子的極性上做文章，而是改變了它們的相位和振幅。

　　The effect is the same, though: Eve will necessarily give herself away if she eavesdrops.Using this technology, QuintessenceLabs is building a 560km QKD link between the JetPropulsion Laboratory in Pasadena, California, which organises many of NASA s unmannedscientific missions, and the Ames Research Centre in Silicon Valley, where a lot of theagency s scientific investigations are carried out.

　　但是結果卻是一樣：如果伊芙竊聽的話，她肯定會露出馬腳的。該公司正使用這個技術，在加利福尼亞州帕薩迪納市的噴氣推進實驗室該實驗室組織了多次美國航空航天局無人駕駛的科研任務，和進行大量機構科學調查的硅谷艾姆斯研究中心之間建立一條560公里的QKD鏈接。

　　A third project, organised by Jane Nordholt of Los Alamos National Laboratory, has justdemonstrated how a pocket-sized QKD transmitter called the QKarD can secure signals sentover public data networks to control smart electricity grids.

　　量子運用于密碼術上的第三個項目，則是由洛斯阿拉莫斯國家實驗室的簡-納德特組織的。這個項目演示了，一個口袋大小的稱為OKarD的QKD發報機是如何捕捉發送到公共數據信息網的信號，來控制智能電網的。

　　Smart grids balance demand and supply so that electricity can be distributed moreefficiently.

　　智能電網可以平衡電力供應與需求，從而讓電力分配更有效。

　　This requires constant monitoring of the voltage, current and frequency of the grid in lotsof different placesand the rapid transmission of the results to control centres.

　　這需要對不同地區電網的電壓，電流和頻率進行不間斷地監測，同時監測結果要快速地傳回到控制中心。

　　That transmission, however, also needs to be secure in case someone malicious wants tobring the system down.

　　然而，也需要確保這種傳輸的安全，以防某些人惡意地破壞這個系統。

　　In their different ways, all these projects are ambitious.

　　雖然他們防止竊聽的方式不一樣，但是這些項目都充滿著遠大的抱負。

　　All, though, rely on local fixed lines to carry the photons.

　　但是，它們都要依靠當地固定的線路來傳送光子。

　　Other groups of researchers are thinking more globally.

　　另外一些研究者的思維則更加全球化。

　　To do that means sending quantum-secured data to and from satellites.

　　要想達到這些研究者的要求，就必須通過衛星來傳送量子安全信息。

　　At least three groups are working on this: Thomas Jennewein and his team at the Institute forQuantum Computing in Waterloo, Canada; a collaboration led by Anton Zeilinger at theUniversity of Vienna and Jian-Wei Pan at the University of Science and Technology of China;and Alex Ling and Artur Ekert at the Centre for Quantum Technologies in Singapore.

　　現在至少有三個研究團體都在進行著這方面的研究。分別是加拿大滑鐵盧的量子研究所托的馬斯-詹內懷恩和他的團隊，維也納大學的安東-塞林格和中國科技大學的潘建國為首的合作團隊，還有新加坡量子技術中心的阿萊克斯-林和阿圖-恩科特團隊。

　　Dr Jennewein s proposal is for Alice to beam polarisation-encoded photons to a satellite.

　　詹內懷恩博士的計劃建立在以艾莉斯為基礎上的，她計劃發送偏振編碼的光子給衛星。

　　Once she has established a key, Bob, on another continent, will wait until the satellitepasses over him so he can send some more photons to it to create a second key.

　　一旦她建立起一個密鑰，那么當衛星運行到位于另一個大陸的鮑伯附近時，鮑伯就可以發送更多的光子給它，就建立起了第二個密鑰。

　　The satellite will then mix the keys together and transmit the result to Bob, who can workout the first key because he has the second.

　　衛星屆時會把這兩個密鑰混合起來，再把結果傳輸給鮑伯，擁有第二個密鑰的鮑伯就可以解開第一個密鑰。

　　Alice and Bob now possess a shared key, so they can communicate securely by normalterrestrial networks.

　　艾莉斯和鮑伯則會擁有一個共享密鑰，所以他們能夠通過正常的地面網絡進行安全地聯系。

　　Dr Jennewein plans to test the idea, using an aircraft rather than a satellite, at some pointduring the next 12 months.

　　詹內懷恩博士計劃在未來一年內的某個時候，用飛機，而不是衛星測試一下這個想法。

　　An alternative, but more involved, satellite method is to use entangled photon pairs. BothDr Zeilinger s and Dr Ling s teams have been trying this.

　　一個更復雜的衛星方法是運用混雜在一起的光子對。塞林格博士和林博士所領導的兩個團隊一直專攻于這個方向。

　　Entanglement is a quantum effect that connects photons intimately, even when they areseparated by a large distance.

　　量子纏結是一種即使光子相隔很遠也能快速連接的量子效應。

　　Measure one particle and you know the state of its partner.

　　如果能測到一個粒子，你就能知道它同伴的狀態。

　　In this way Alice and Bob can share a key made of entangled photon pairs generated on asatellite.

　　通過這種方式，艾莉斯和鮑伯能夠共享一個在衛星上產生的，纏結光子對組成的密鑰。

　　Dr Zeilinger hopes to try this with a QKD transmitter based on the International SpaceStation.

　　寒林格博士希望能夠用國際空間站的QKD發射器進行這項試驗。

　　He and his team have been experimenting with entanglement at ground level for severalyears.

　　他和他的團隊在地面上進行這種纏結試驗已經幾年了。

　　In 2007 they sent entangled photon pairs 144km through the air across the Canary Islands.

　　2007年，他們利用空氣讓光子對穿過了加那利群島，傳輸了144公里。

　　Dr Ling s device will test entanglement in orbit, but not send photons down to Earth.

　　林博士的設備將會在軌道上測試纏結效應，但是不會把光子傳回到地球。

　　If this sort of thing works at scale, it should keep Alice and Bob ahead for years.

　　如果這方面工作的規模不斷擴大，那么艾莉斯和鮑伯將會保持領先很多年。

　　As for poor Eve, she will find herself entangled in an unbreakable quantum web.

　　對于可憐的伊芙來說，她會發現自己身陷于一個牢不可破的量子網中無法解脫。

　　詞語解釋

　　1.give to 送給，贈給，提供

　　What does physically making music give to you?

　　實際地創作音樂給你帶來了什么收獲?

　　Another is the support harvard faculty give to theircolleagues.

　　另一條經驗是，哈佛的教師給予同事的支持。

　　2.look for 尋找

　　Look for a second job or odd jobs.

　　找第二份工作或者做零工。

　　Always look for ways to improve.

　　總是尋找不同的方法改進。

　　3.derive from 起源;取自

　　That includes the stem cells themselves, which derive from ur stem cells found inembryos.

　　而干細胞則是來自胚胎中的ur干細胞。

　　One answer is the indirect benefit that investors derive from addressing the economic risksof global warming.

　　答案之一是間接的好處，投資者從處理全球變暖的經濟風險中得到好處。

　　4.work out 解決;作出;鍛煉

　　Sometimes even our best laid plans don t work out the way we d hoped.

　　有時候我們最精心制定的計劃也未必按照我們所希望的方式實現。

　　Can you work out this problem?

　　你能算出這道題嗎?