Like many in the industry, Photonics Media is watching the world of quantum research as it unfolds. With quantum-themed headlines appearing daily, it can be difficult for the nonexpert to discern which information is ‘need to know,’ which is thought leadership, and which is theoretical. This interview with John Prisco looks at quantum key distribution. Prisco is CEO and president of Quantum Xchange Inc., which has built the first QKD network in the U.S. He is a 30-year veteran of the cyber-security and telecom industries and has an advanced degree in quantum optics from MIT. What is ‘quantum key distribution’ and what is the role of photonics? Quantum key distribution (QKD) exploits the properties of quantum mechanics to securely transmit cryptographic keys between two parties using laser-generated photons of light. The quantum properties of photons in the beams are coded into binary ones and zeroes instead of electronic bits. Because QKD is rooted in the laws of physics, not mathematical computations like traditional encryption, if a third party intercepts the beam, the mere act of being observed changes its quantum state, making the keys useless to an attacker and theoretically unbreakable. Does QKD primarily concern corporations and large institutions? QKD and its no-clone, no-eavesdropping properties are best suited for commercial organizations and government agencies seeking the highest levels of protection available today for their most critical assets, communication channels, and long-shelf-life data. As the reality of quantum computing approaches, companies and other organizations need to stay one step ahead of the potential computational power that could render today’s encryption algorithms obsolete. They must also protect against a more immediate threat: harvesting attacks. These happen when nefarious actors steal encrypted data and classical encryption keys that were used to encrypt the data, stockpile it, and wait for the day when a quantum computer can break the encryption keys in mere minutes. We’re seeing more and more organizations relying on a zero-trust model and an encrypt-everything approach. Quantum readiness, or crypto agility, is critical to protecting and securing data and fending off new threats. As a result, we work with highly regulated, high-risk organizations in finance, critical infrastructure, health care, telecommunications, and government agencies that need to protect long-shelf-life data now. Who is competing for quantum supremacy, and why? Is quantum supremacy primarily a security issue, and what are the implications across sectors? “Quantum supremacy” is a term first coined by Caltech professor John Preskill in 2012 to describe the point where quantum computers can do things that classical computers can’t, regardless of whether those tasks are useful. With that new term, he wanted to emphasize that this is a privileged time in the history of our planet, when information technologies based on principles of quantum physics are ascendant. Since then, tech giants like IBM, Google, and Microsoft have been racing to reach quantum supremacy and bring the power of a quantum computer to market. In October 2019, Google confirmed it had achieved quantum supremacy. To demonstrate supremacy, Google used its quantum machine to successfully perform a test computation in just 200 seconds that would have taken the best-known algorithms in the most powerful supercomputers thousands of years to accomplish. Google’s accomplishment represents a major milestone and serves as a reminder that we need to be prepared for quantum computers. There’s no arguing that when a quantum computer overtakes traditional, “classical,” binary computers, our lives will never be the same. Quantum computers will bring us far more accuracy in modeling nearly everything, spurring the development of breakthroughs in science, the synthesis of new medications to save lives, machine learning methods to diagnose illnesses sooner, materials to make more efficient devices and structures, and financial strategies to live well in retirement. But, with the arrival of the next great computing paradigm comes new threats. A quantum computer will be able to break the majority of today’s traditional encryption — meaning, anything password-protected will be easily broken. The threat is real and happening today with the rise of harvesting attacks mentioned earlier. It’s worth putting the measures in place now to protect our high-value data and make our encryption quantum-safe.