review articles

CYBER SECURITY DEALS with the protection of computer systems from attacks that could compromise the hardware, software or information. These attacks, by allowing unauthorized use, could leak private information and cause damage or disruption. In the future, the part of everyday life and economy requiring computer systems is bound to increase further and become fully dominant. Cyber warfare and cyber crime will be common and the role of cyber security crucial.

SINCE THE COMPUTER systems (and attackers) evolve both in hardware and software, the constant evolution of this field is of high importance. Arguably the most dramatic development that one can envision is a change in the paradigm of computational model used.

Quantum technologies appear to bring us close to
such a change. Here, we explore the research field that
lies on the intersection of cyber security and quantum
technologies research.

The dawn of the quantum technologies era. One of the major scientific revolutions of the 20th century was the development of quantum theory. From its early days, 33 all the way until the development of the full mathematical formalism38 and the subsequent development of first wave of applications (for example, transistors, laser, superconductors, among others) quantum theory has been very successful in many different settings being confirmed in unprecedented accuracy (record accuracy of 10–8 for the anomalous magnetic dipole moment). 24 Crucial in this first wave of applications was the new understanding of nature that quantum theory provided. However, the ability to control quantum systems as desired was limited, putting restrictions on the class of technological applications that one could envision.

In recent years this has changed16 and the control of quantum systems has advanced considerably, while further progress appears very plausible in the near future due to the increased interest and investments as well as the scientific breakthroughs that have already occurred. Many countries all around the globe have launched national

Cyber
Security
in the
Quantum Era
DOI: 10.1145/3241037

Quantum systems will significantly affect the field of cyber security research.

BY PETROS WALLDEN AND ELHAM KASHEFI

key insights

˽ Quantum computers will pose a significant threat for cyber security. When large fault-tolerant quantum computers are constructed the most commonly used cryptosystems will break. Therefore dealing with this threat is crucial and timely.

˽ Securing fully classical protocols against quantum-technology-equipped adversaries is possible but requires extra care that goes beyond a careful choice of cryptosystems.

˽ Quantum technologies will also have a positive impact on cyber security. Quantum devices with current state-of-the-art technology can be used to enhance the security by achieving tasks impossible classically, such as, secret-key expansion with perfect security. Since quantum computers will become an integral part of our future network of communications and computations, we need to develop practical ways to use the quantum computers with same security guarantees with those of secure (classical) computing.