Secure Quantum Pattern Communication

Abstract

We propose a multimode modulation scheme for continuous-variable (CV) quantum communications, which we call quantum pattern encoding. In this setting, classical information can be encoded into multimode patterns of discretely modulated coherent states, which form instances of a communicable image space. Communicators can devise arbitrarily complex encoding schemes that are degenerate and highly nonuniform, such that communication is likened to the task of pattern recognition. We explore initial communication schemes that exploit these techniques and that lead to an increased encoding complexity. We discuss the impact that this has on the role of a near-term quantum eavesdropper; formulating new realistic classes of attacks and secure communication rates.