量子加密竞赛方兴未艾，中国已领先一步

SAN FRANCISCO — The world’s leading technology companies, from Google to Alibaba in China, are racing to build the first quantum computer, a machine that would be far more powerful than today’s computers.

旧金山——从谷歌到中国的阿里巴巴，世界上领先的科技企业都在竞相建造第一台量子计算机，它将比今天的计算机强大得多。

This device could break the encryption that protects digital information, putting at risk everything from the billions of dollars spent on e-commerce to national secrets stored in government databases.

量子设备可以破解用于保护数字信息的加密，使所有的数字信息面临危险，从数十亿美元的电子商务支付，到存储在政府数据库的国家机密。

An answer? Encryption that relies on the same concepts from the world of physics. Just as some scientists are working on quantum computers, others are working on quantum security techniques that could thwart the code-breaking abilities of these machines of the future.

有应对的办法吗?那就是依赖于物理世界相同概念的加密。正如一些科学家在研究量子计算机一样，另一些科学家也在研究量子安全技术，这种技术可以阻止这些未来机器的密码破译能力。

It is a race with national security implications, and while building quantum computers is still anyone’s game, China has a clear lead in quantum encryption. As it has with other cutting-edge technologies, like artificial intelligence, the Chinese government has made different kinds of quantum research a priority.

这是一场可能影响国家安全的竞赛，尽管建造量子计算机仍是大家都在干的事情，但中国在量子加密方面已明显领先。与中国在人工智能等其他尖端技术上的做法一样，政府已经把各种量子研究列为重点。

“China has a very deliberate strategy to own this technology,” said Duncan Earl, a former researcher at Oak Ridge National Laboratory who is president and chief technology officer of Qubitekk, a company that is exploring quantum encryption. “If we think we can wait five or 10 years before jumping on this technology, it is going to be too late.”

“中国对拥有这项技术有一个经过深思熟虑的战略，”邓肯·厄尔(Duncan Earl)说，他曾是橡树岭国家实验室(Oak Ridge National Laboratory)的研究员，现在是探索量子加密技术的Qubitekk公司的总裁兼首席技术官。“如果我们认为我们可在加入这项技术之前等个五年、十年的话，那将太晚了。”

Quantum computing is based on quantum mechanics, the science that explains the strange behavior exhibited by extremely small particles of matter.

量子计算以量子力学为基础，量子力学是解释极小的物质粒子所表现出的奇怪行为的科学。

With traditional computers, transistors store “bits” of information, and each bit is either a 1 or a 0. Those are the fundamental slices of data that tell a computer what to do.

在传统计算机中，晶体管存储信息的“位”，每个位不是1就是0。这些是告诉计算机该如何操作的基本数据单位。

When some types of matter are extremely small or extremely cold, they behave differently. That difference allows a quantum bit, or qubit, to store a combination of 1 and 0. Two qubits can hold four values at once. As the number of qubits grows, a quantum computer becomes exponentially more powerful.

当物质非常小或非常冷时，它们会发生不同的行为。这种差异允许一个量子位(qubit)存储1和0的组合。两个量子位可以同时保存四个值。随着量子位数量的增长，量子计算机的计算能力指数式地增长。

Like quantum computing, quantum encryption relies on the nonintuitive behavior of very small objects. The codes that keep data secret are sent by photons, the tiniest particle of light. With the right equipment it is easy to tell if they have been tampered with, not unlike the seal on an aspirin bottle. If carried out properly, the technique could be unbreakable.

和量子计算一样，量子加密技术依赖于非常小的物体的非直觉行为。保护数据秘密的密码是通过光子发出的，光子是最小的光粒子。使用合适的设备，就很容易判断密码是否被擅自改动过，这就像是阿司匹林药瓶上的封条是否破损。如果使用得当，量子加密技术可能是牢不可破的。

There is no guarantee that a viable quantum encryption network could be built over long distances. But if it does happen, China’s willingness to experiment and put government, academic and commercial resources behind the effort could have a big payoff.

不能保证一个可行的量子加密网络可以在长距离上建立起来。但如果能够建立的话，中国愿意进行试验，并将政府、学术和商业资源投入其中的做法，可能会带来巨大回报。

The country has invested tens of millions of dollars building networks that can transmit data using quantum encryption. Last year, a Chinese satellite named Micius, after an ancient philosopher, managed a video call between Beijing and Vienna using quantum encryption. A dedicated quantum communication network between Beijing and Shanghai was also put into operation last year, after four years of planning and construction.

中国已经在建设使用量子加密传输数据的网络上投入了数千万美元的资金。去年，中国一颗以古代哲学家墨子的名字命名的卫星，使用量子加密技术成功实现了北京与维也纳之间的视频通话。经过四年的规划和建设，北京和上海之间的专用量子通信网络也于去年投入使用。

For now, quantum encryption works only over a limited distance. The satellite link between Beijing and Vienna stretched this limit to a record 4,630 miles. On the ground, using optical fiber lines, the ceiling is about 150 miles.

目前，量子加密只能在有限的距离内工作。北京和维也纳之间的卫星连接将这个距离扩大到了创纪录的4630英里(约合7451公里)。在地面上，使用光纤线路的最大距离大约是150英里(约合240公里)。

Among China’s investments in quantum encryption, the Micius satellite has received the most attention. The University of Science and Technology of China, the government-backed university that helped launch Micius, led the construction of the ground network, which spans about 1,200 miles — perhaps a hint of aspirations for drastic improvement.

在中国对量子加密技术的投资中，“墨子号”卫星受到的关注最多。政府出钱支持的中国科学技术大学帮助发射了“墨子号”卫星，科大也在牵头建设总长约1200英里(约合1930公里)的量子通信地面网络。

The governments of Anhui and Shandong Provinces, through which the fiber-optic network passes, together invested $80 million in the project. Like all major infrastructure projects in China, the plans have had high-level support from the Chinese government.

光纤网络途经的安徽省和山东省政府总共为项目投资了8000万美元。与中国所有的重大基础设施项目一样，量子通信项目也得到了中国政府高层的支持。

This main line is being extended to other cities and regions. The goal by 2030 is a Chinese-built network for sharing quantum encryption keys across the globe.

这条干线正在延伸到其他城市和地区。中国的目标是，在2030年前，建成一个连接全球各地的分享量子加密密钥的网络。

Some security experts question the effectiveness of quantum encryption. Because it is so new, it has not been put through anywhere close to the rigorous testing that would give it a stamp of approval from skeptical cryptographers.

一些安全专家对量子加密的有效性有怀疑。因为这种技术如此之新，它还没有经受过任何可以让持怀疑态度的密码学家对技术表示认可的严格测试。

But Chao-Yang Lu, a professor of physics at the University of Science and Technology of China, said the Beijing-Shanghai quantum network was a significant upgrade.

但科大物理系教授陆朝阳说，量子通信京沪干线是一次重大的升级。

With communications sent by traditional means, eavesdroppers can intercept the data stream at every point along a fiber-optic line. A government could tap that line just about anywhere. Quantum encryption cut the number of vulnerable spots in the Beijing-Shanghai line to just a few dozen across 1,200 miles, Professor Lu said.

使用传统通信方式时，窃听者可以在光纤线路上的每个点拦截数据流。政府可以在通信线路的任何地方进行窃听。陆朝阳说，量子加密技术让长达1200英里的京沪干线上易受攻击的点减少到了几十个。

“We admit that it’s an intermediate solution,” he said. “It’s not the final solution. But it’s already a huge improvement in terms of security.”

“我们承认这是一个中间阶段的解决方案，”他说。“这不是最终的解决方案。但就安全而言，这已经是一个巨大的进步。”

In the United States, the government and industry have viewed quantum encryption as little more than a science experiment. Instead, researchers have focused on using ordinary mathematics to build new forms of encryption that can stand up to a quantum computer. This technology would not require new infrastructure.

在美国，政府和业界认为量子加密不过是一项科学实验。所以，研究人员的精力一直集中在使用现有的数学来构建新的、可对抗量子计算机的加密方法。这种做法不需要新的基础设施。

But now, spurred by activity in China and recent advances in quantum research, some in the United States are playing catch-up.

但现在，在中国的做法和最近的量子研究取得进展的推动下，美国有些人正在努力追赶。

Qubitekk, a Southern California start-up, is working to secure power grids in Tennessee using the technology. A second start-up, Quantum Xchange, is building a quantum encryption network in the Northeast, hoping to serve Wall Street banks and other businesses. Researchers at Stony Brook University on Long Island are preparing a third venture.

南加州初创企业Qubitekk正在使用量子加密技术来保护田纳西州的电网。另一家初创公司Quantum Xchange正在美国东北部建设一个量子加密网络，希望为华尔街银行和其他企业提供服务。位于长岛的石溪大学(Stony Brook University)的研究人员正在准备成立另一家企业。

Small start-ups like Qubitekk are unlikely to match the millions of dollars in infrastructure already created in China for quantum encryption. But many experts believe the more important work will happen in research labs, and the Department of Energy is funding a test network in Chicago that could eclipse the kind of systems deployed in China.

像Qubitekk这样的小型初创企业不太可能像中国为量子加密建立基础设施那样，投入数百万美元。但许多专家认为，更重要的工作将发生在研究实验室，美国能源部正在为芝加哥的一个测试网络提供资金，该网络可能会让中国使用的系统相形见绌。

The Los Alamos and Oak Ridge National Laboratories are working with Qubitekk to secure power grids with quantum technology, and Quantum Xchange is moving equipment into 60 Hudson Street, the old Western Union telegraph hub, which now serves as an internet hub for Lower Manhattan.

洛斯阿拉莫斯国家实验室(Los Alamos National laboratory)和橡树岭国家实验室都在与Qubitekk合作，使用量子技术保护电网。Quantum Xchange正在把设备搬到哈德逊街60号，原西联(Western Union)电报中心所在地，现在是曼哈顿下城的一个互联网中心。

Quantum Xchange is building a quantum encryption link between Manhattan and Newark, with plans to connect big banks operating in the two cities. Eventually, it hopes to extend this network up and down the East Coast.

Quantum Xchange正在曼哈顿和纽瓦克之间建设量子加密连接，并计划把在这两个城市运营的大型银行连接起来。公司最终的希望是把这个量子加密网络延伸到整个东海岸。

At places like the University of Chicago, researchers hope to go a step further, exploring what are called quantum repeaters — devices that could extend the range of quantum encryption.

在像芝加哥大学这样的地方，研究人员希望再上一层楼，他们正在探索所谓的量子中继器，即能够延伸量子加密距离的设备。

“We’re not there yet,” said David Awschalom, a professor at the University of Chicago who oversees much of the university’s quantum research. “But I am confident this will happen in the next couple of years.”

“我们还没有做成，”芝加哥大学(University of Chicago)教授戴维·奥沙洛姆(David Awschalom)说。“但我相信，这将在未来几年发生。”

Quantum communication techniques require new hardware. This includes vast networks of fiber lines — and perhaps satellites — as well as specialized devices capable of detecting individual photons of light.

量子通信技术需要新的硬件，包括庞大的光纤网络——或许还有卫星——以及能够探测单个光子的专门设备。

As Qubitekk worked on quantum encryption networks, it could not obtain the special light detectors it needed to do the work. The start-up originally bought detectors from a small manufacturer in New Jersey, Princeton Lightwave. But in April, this lone American manufacturer handed the detector business over to a company in China, RMY, and Qubitekk’s supply line ran dry.

随着Qubitekk建设量子加密网络工作的进展，公司发现无法获得完成这项工作所需的特殊光子探测器。这家初创公司最初是从新泽西州的一家叫普林斯顿光波(Princeton Lightwave)的小型制造商那里购买了这种仪器。但今年4月，这家美国制造商将光子探测器的业务转给了一家中国公司RMY，Qubitekk的供应链断了。

RMY has promised hardware to Qubitekk but recently told it that, because of production issues, additional detectors won’t be available until March.

RMY已经承诺向Qubitekk提供硬件，但最近通知它，由于生产问题，下一批探测器只能在明年3月后交货。

Small companies in Europe are selling somewhat similar detectors, and labs across the globe are developing a more advanced type of hardware. But for now, supplies, particularly in the United States, are slim.

欧洲的一些小公司也销售类似的探测器，而且全球各地的实验室正在开发一种更先进的仪器。但就目前而言，这种探测器的供应很有限，尤其是在美国。