Continuous-Variable Quantum Key Distribution with Multi-Mode Signals

Continuous Variable Quantum Key Distribution (CV-QKD) uses amplitude and phase modulation of light in order to exchange secure keys between two legitimate users. Since the intensity of the CV-QKD signal is extremely low, the quantum uncertainty associated with the signal introduces noise in the signal measurement while at the same time provides security under the laws of quantum physics. CV-QKD resembles to classical coherent communication in many of its aspects where digital signal data processing on the measurement data is a most common one.

With this research, we are aiming to develop efficient data processing in .NET environment for multi-mode CV-QKD systems for fibre as well as for free-space communication channels. The primary goal of this research is to develop CV-QKD system that offers high signal to noise ratio by utilizing multiple modes of the quantum signals. It also includes programming and interfacing of data generation and acquisition devices, on board data manipulation and reconciliation. Particular emphasis is given on error correction codes running in graphics processing units. The research is also studying the vulnerabilities associated with multi-mode CV-QKD systems.