Practical Quantum Cryptography

Research Mentor: Walter Krawec

Quantum cryptography promises a future communication infrastructure, secure against computationally unbounded adversaries. One of the most celebrated results in this field is the ability to distribute a key between two parties where security is guaranteed against any adversary bounded only by the laws of physics. This is in stark contrast to classical key distribution where it is necessary to make computational assumptions on the adversary to prove security. By harnessing the power of quantum communication, users may securely communicate regardless of any computational developments an adversary may make, including any future developments in quantum computing technology. Furthermore, quantum communication is a practical technology today with several experimental and commercial activities promoting its development with plans to implement it in some city and 5G networks. However, numerous challenges remain before it can see wide-scale consumer adoption. Two particularly challenging problems are cost and efficiency. By reducing both, we will be able to begin integrating this important technology into a much larger class of applications including embedded devices.

Quantum communication relies on the transmission of quantum bits or qubits. Practically, qubits are often physically realized as photons sent over fiber channels or through free space. To maintain quantum security, single photons must be prepared and, unlike classical optical communication, these signals cannot be amplified. This decreases the practical range and speed of quantum communication systems. Furthermore, the cost needed to purchase hardware capable of making accurate measurements of these photons is currently prohibitive. What is needed are new protocols that both mitigate cost, by requiring fewer measurement devices, while also being more robust to noise and photon loss. The development of these protocols, and their subsequent security analysis, will lead to greater insights in the capabilities of quantum communication and information science. Furthermore, such developments will have broad impact to our society, allowing us to confidently switch to a new, quantum-secure, communication infrastructure.

Components for Student Participation

Students will work on analyzing novel protocols, both quantum and classical. They will construct simulators to model the dynamics of the protocols under investigation. Students will also be involved in security analyses of these systems. As quantum technology becomes more and more prevalent, the need to educate students on these systems is of vital importance. Students will be introduced to the basics of quantum computation and communication through this research. Furthermore, they will also develop a mindset needed to think of secure systems, both quantum but also classically, giving them practical knowledge of computer security in general, a vital necessity in today's world.