Quantum Steganography in an Optical Channel

Steganography is an alterantive to cryptography, where information is protected by secrecy — being disguised as innocent communications or noise — rather than being scrambled. In this work we develop schemes for steganographic communication using Fock and coherent states in optical channels based on disguising the communications as thermal noise. We derive bounds on their efficiency in the case of an all-powerful eavesdropper, and provide explicit methods of encoding and error correction for the noiseless channel case.