Six researchers at four universities, including the UA College of Engineering's Mark Neifeld and Ivan Djordjevic, have won a multimillion-dollar U.S. Department of Defense award to explore quantum key encryption methods far more advanced than cryptography technology in use today.
The project, "Fundamental Research on Wavelength-Agile, High-Rate Quantum Key Distribution (QKD) in a Marine Environment," is a combined effort between the UA and the University of Illinois at Urbana-Champaign, which is the project lead, and also Duke University and Boston University. In total, the project will be funded at $1.5 million annually for up to five years.
Quantum key distribution uses quantum mechanics to guarantee secure communication. It enables two parties to automatically produce a shared random secret key known only to them, which can then be used to encrypt and decrypt messages sent over a standard communication channel.
"One of the simplest approaches to QKD involves two parties sharing entangled photon pairs via optical fiber," explained Neifeld who, along with Djordjevic, holds a joint appointment in electrical and computer engineering and optical sciences.
Using adaptive optics and signal processing approaches, the UA portion of the project, awarded at $1.86 million over the project period, involves simulating, assessing and finding ways to overcome the low data rates and security levels. Such issues are caused by light-distorting atmospheric conditions, such as turbulence, scattering and absorption.
Traditional key distribution security methods leave communications networks vulnerable to cyberattacks because attackers can figure out how to crack the complex mathematics underpinning these methods.
Quantum key distribution, however, uses light particles. According to the laws of quantum physics, such encryption keys are inherently secure.
"QKD relies on the fundamental laws of quantum mechanics to ensure that the encryption is impossible to break," Neifeld said.
In the realm of quantum physics, the mere act of observing an ultra-small particle influences the physical processes taking place. So an eavesdropper trying to intercept a quantum communication inevitably would leave detectable traces. Any attempt to steal the key would reveal the hacker's presence and prompt the QKD to abort that generation of the key.
QKD has been proven in laboratory and controlled environments, and there are a few efforts underway to commercialize QKD technology.
However, it is not without its challenges in the real world, especially when it comes to sharing the key.
Some of the issues are associated with photon detection, transmission distance and rate of key generation. The current project involving Neifeld and Djordjevic will take a number of approaches to overcoming the challenges.
"To date, QKD has only been effectively implemented using optical fibers with low secure key rates," Neifeld said.
"When we succeed at this project, we will have a secure method of communication through the air between ships and air vehicles at data rates sufficient to support real-time exchange of secret information."