Experimental Demonstration of Quantum Low Probability of Intercept for Ultra-Secure Communication

Abstract

Secure communication systems utilize encryption with shared keys between the sender and receiver of the encrypted message. For added security, the encrypted message can be hidden within a significant amount of noise so that the eavesdropper could not even extract the actual encrypted message, let alone decrypt it. However, such a system, called low probability of intercept (LPI), also uses a shared key which is susceptible to security failure caused by key disclosure, just like encryption systems. A quantum version of LPI, or QLPI, operates entirely differently: the key for quantum low probability of intercept (QLPI) is transient and not shared, and its security is based on the quantum no-cloning theorem. In this work, we will present a tabletop proof-of-concept experiment to demonstrate QLPI, achieving errorfree secure communication at an internet-compatible rate of 0.5 Gbps over the equivalent of 50 km of telecom fibers.