Investigating the Effectiveness of Measurement-Device-Independent Quantum Key Distribution with Weak Coherent Pulses

Quantum key distribution (QKD) is a quantum cryptographic task that allows a random secret key to be generated and communicated between two parties in the presence of an eavesdropper. Although QKD systems are theoretically foolproof and completely secure according to the laws of quantum mechanics, many security loopholes have been found in practice. Measurement-device-independent quantum key distribution (MDI-QKD) improves upon previous QKD systems by removing all detector side-channels, therefore rendering many of the loopholes obsolete. However, in order to successfully implement MDI-QKD, the sources (representing the two communicating parties) must be indistinguishable. We will be implementing MDI-QKD with two independent sources of light coming from attenuated laser pulses, or resonant cavity LEDs; as a result, the sources will be rigorously tested and characterized to determine how indistinguishable they truly are.