Effects of quantum noises on χ state-based quantum steganography protocol.

Since the good application of quantum mechanism in the field of communication, quantum secure communication has become a research hotspot. The existing quantum secure communication protocols usually assume that the quantum channel is noise-free. But the inevitable quantum noise in quantum channel will greatly interferes the transmission of quantum bits or quantum states, seriously damaging the security and reliability of the quantum system. This paper analyzes and discusses the performance of a χ state based steganography protocol under four main quantum noises, i.e., Amplitude Damping (AD), Phase damping (Phs), Bit Flip (BF) and Depolarizing (D). The results show that the protocol is least affected by amplitude damping noise when only the sender's first transmission in quantum channel is affected by quantum noise. Then, we analyze the performance of the protocol when both the sender's two transmissions are affected by quantum noise, and find that the specific combination of different noises will increase the performance of the protocol in quantum noisy channel. This means that an extra quantum noise can be intentionally added to quantum channel according to the noise intensity, so that the protocol can improve performance under the influence of quantum noises. Finally, the detailed mathematical analysis proves the conclusions.