In this series, we’ll be exploring the emerging technology of quantum computing—what it is, what it means, where it’s headed. In particular, we’ll explore the changes brought to bear by the new technology, and how these changes are likely to transform some of our core assumptions about information architecture, infrastructure, and above all, security.
Today, we’ll discuss some definitions and distinctions, and get an overview of quantum computing and its current status in the technological landscape. In later posts, we’ll unpack the shape of the opportunities that quantum computing offers when it comes to optimizing applications relevant to financial services. Finally, we’ll look to the next few decades as quantum computing moves from a cloud-based structure to the “last mile” of devices in proximity to the user.
What is Quantum Computing?
Right now, your phone, laptop and e-mail server all perform computing and memory tasks based on electrons, which are either flowing (on) or not (off). Ones and zeros.
Quantum computers can encode and process information using atomic particles and quasi-particles, rather than simply measuring their presence or absence. This gives us more options than a simple “on or off,” making each computing request more varied and complex. Like speaking naturally as opposed to communicating in Morse code, communicating one word at a time is more efficient and complex than one letter at a time.
Because a quantum bit, or qubit, can hold multiple variables at the same time (“superposition”), computing can happen at rates that are literally millions of times more powerful than conventional electronic systems1 (see Figure below).
Quantum computers can also take advantage of a phenomenon known as quantum entanglement. When we apply an outside force to entangled particles, they react in a correlated way regardless of whether or not they are separated by a large physical distance (e.g., on the other side of the universe). For instance, entangled particles can be set up so that each particle is always observed in the opposite state from the other particle. This allows us to look at the first particle and know what’s happening with the second particle even though it’s somewhere else.
We would like to exploit this phenomenon for reliable and fast communication in situations where regular communications lag due to extreme distance, like satellites or even space probes. Unfortunately, quantum communication protocols also require classical communication to extract useful information. In essence, it is impossible to use entangled particles for faster-than-light communications, or to entirely replace classical communications, at least as far as we know today.
However, we can still use entanglement to transmit multiple bits of classical information using a single qubit (superdense coding) and to securely transmit cryptographic keys.
How does quantum computing impact existing cryptographic systems?
Conventional security relies on either the Public Key Certificate (PKC) model or the Secret Key Certificate (SKC) model:
- In a public key system, you can let me encode a message to you, but only you can decode it. You essentially give me one encryption key, so I can lock the message, but only you have a second key that can unlock it.
- In a secret key system, there’s only one key involved to both encrypt and decipher the message, and the key becomes encoded inside the message itself. Someone can intercept the message, but without an intact key, their efforts are useless.
Public key encryption gives hackers something to start with in terms of guessing what the private key might look like, but the staggering number of variables among 128 bits of data would take conventional computers thousands of years to guess. The power of the security assumption rests on it being impractical to hack.
In fact, public key encryption is so impractical to hack that we widely use it today for the secure internet communication protocols used for online shopping and banking, such as https and ssl. Unfortunately, there are known quantum algorithms (such as Shor’s Algorithm) that in the future will be able to break the public key algorithms we use today, rendering all our sensitive internet communications vulnerable to decryption.2
Yet, all is not hopeless. Organizations across the world, such as the National Institute of Standards and Technology (NIST), are working on developing public key algorithms that are secure against both classical and quantum computers.3 Additionally, secret key systems are not believed to be vulnerable to quantum computers.
Where Are We Now?
Currently, the most advanced universal quantum computer can only operate with 50 noisy qubits —nowhere near complex or stable enough to supplement conventional supercomputers to any significant degree. There’s currently no way to maintain quantum computing memory for longer than half an hour, and without amplification or entanglement, quantum computing signals deteriorate after only 100 km.
However, research efforts are underway:
- In 2018, Chinese Academy of Science researchers managed to engineer a 64-qubit quantum simulator.4
- Researchers from the University of Tokyo recently developed a system for optical quantum computing that uses a single circuit.5
- In August of 2016, China launched a satellite as part of the Quantum Experiments at Space Scale program,6 and in the summer of 2017, the Chinese Academy of Sciences deployed its quantum communications work through the first ever quantum-safe and “unhackable” video call relying on entanglement.7
Currently, there is only one vendor with commercially available quantum computers: Canada’s D-Wave Systems. Other quantum computing resources are based in research laboratories, with new start-ups in the field announced daily. Some of these computers are exposed via application programming interfaces (APIs) to either the public and/or partners.
For computationally intensive projects, such as the invention of new man-made materials or new drugs, quantum computing is the obvious and inevitable solution—though we’re a decade away from seeing quantum-based accelerators as commonplace.
In our next installment, we’ll take a look specifically at the disruptive nature of quantum computing in regards to finance, privacy and global intelligence. When a password system is built on the assumption that it would take a thousand years to crack, what happens when a quantum computer finds a key in seconds?
In the meantime, if you’d like to learn more, you can read our report “Think Beyond Ones and Zeros”.
- “When can Quantum Annealing win?” Google Research Blog, December 8, 2015. Access at: https://research.googleblog.com/2015/12/when-can-quantum-annealing-win.html.
- “Post-Quantum Cryptography.” Computer Security Resource Center, February 20, 2018. Access at: https://csrc.nist.gov/Projects/Post-Quantum-Cryptography.
- Daniel J. Bernstein, “Introduction to post-quantum cryptography.” July 18, 2017. Access at: https://pqcrypto.org/.
- “64-Qubit Quantum Circuit Simulation.” February 20, 2018. Access at: https://arxiv.org/abs/1802.06952”.
- “University of Tokyo pair invent loop-based quantum computing technique.” Japantimes.co.jp, September 24, 2017. Access at: https://www.japantimes.co.jp/news/2017/09/24/national/science-health/university-tokyo-pair-invent-loop-based-quantum-computing-technique/#.WisBY0xFwdU.
- “China launches world’s 1st quantum satellite.” Cbc.ca, August 16, 2016. Access at: http://www.cbc.ca/news/technology/china-quantum-satellite-1.3349383.
- “Scientists made the first ‘unhackable’ quantum video call.” Engadget.com, October 2, 2017. Access at: https://www.engadget.com/2017/10/02/scientists-china-unhackable-quantum-video-call.