The Design And Analysis Of Quantum Steganography And Quantum Watermarking Protocols

Quantum computation has rapid processing capacity, and it is the great threat to classical cryptography with computational security. This threat makes scientists begin to consider the quantum cryptography based on the principle of quantum mechanical. Quantum cryptography has fast developed in theoretical basis and experimental technology. With its ongoing developments, quantum cryptography starts to focus on different research fields. As one new research field of quantum cryptography, quantum information hiding has some advantages over classical information hiding and has been one important part of quantum cryptography. Meanwhile, quantum computation can efficiently solve some problems in image processing, which are considered to be intractable on any classical computer. With the development of quantum information theory, researchers begin to pay attention to the study of quantum images. However, quantum images are still in theory exploration stage. Therefore, the research about quantum images will be a very promising research subject, not only in the current time of classical image processing but also in the future quantum information age.Quantum steganography and quantum watermarking are two important subtopics of quantum information hiding. Quantum watermarking, which combines quantum information hiding with quantum images, supplies a novel research approach for quantum information hiding. This paper studies two kinds of quantum information hiding protocols:quantum steganography and quantum watermarking. Its innovations are provided as below:1) The secrecy evaluation of quantum steganography protocols: Secrecy is an important method to mesure the performance of quantum steganography protocols. The secrecy evaluation menthod is an effective approach to do secrecy analyze. In order to study the secrecy of quantum steganograhy protocols, this paper reclassifies the quantum steganography protocol. At first, a secrecy evaluation methd is analyzed for quantum steganography protocols with the carrier channel, which are open quantum channels. Then, a new secrecy evaluation method, which is based on trace distance, is proposed for quantum steganography protocols with the carrier channel, which are closed quantum channels. Moreover, in order to verify its availability, the new method is used to analyze the secrecy of the existing quantum steganography protocols. This method supplies a measure for the secrecy of new quantum steganography protocols in later chapters.2) Novel quantum steganography protocols:Firstly, based on probability measurements, a novel quantum stegangraphy protocol is proposed. This protocol utilizes positive operator-valued measurement operators to achieve the embedding of secret message. Secret message does not influence on normally reading cover data. Moreover, receivers don’t need to publish the cover data when they extract the secret message. It ensures the protocol has the better properties in secrecy and security. Its security doesnot rely on other quantum cryptography protocols, and can be used in common quantum communications. Secondly, due to the environment noise and decoherence, quantum states decay and change easily. Moreover, there are a few quantum steganography protocols to fit quantum noisy channels in existing protocols. It is meaningful to make a quantum steganography fit quantum noisy channels. This paper extends the presented protocol to quantum communications happened in quantum noisy channels, and proofs that the protocol fits quantum noisy channels. Finally, this paper uses foregoing the secrecy evaluation method to do quantitative analysis for the secrecy of these two quantum steganography protocols, and shows they have good secrecy. Moreover, the quantum states used in the protocol is non-entangled single particle states. This makes our protocols be feasible with the current experimental technology.3) Quantum images and quantum watermarking:Based on the previous research for quantum images, this paper presents a spatial domain quantum watermark protocol, which uses a flexible representation of quantum images as its cover images. In order to give its quantum circuit, a new multi-control quantum rotation gate is designed. This quantum gate makes the protocol can flexibly control the embedding of watermark images. Moreover, in order to preprocess watermark images, an image scrambling method and its quantum circuit, which aims at this kind of quantum images, is given in the watermark protocol. Feasible quantum circuits can make sure the protocol follow the quantum mechanics principle and be feasible under current experimental conditions. Existing quantum watermark protocols have not given integrated quantum circuits used to achieve these protocols. Due to the problem, this paper gives the feasible quantum circuit for the presented protocol. According to the given quantum circuits, simulation experiments, which are related to the embedding algorithm and the image scrambling method of the presented watermark protocol, are implemented in classical computers. Simulation results verify that the given quantum circuit are feasible, and show the watermark protocol does well in imperceptibility, security and embedding capacity. Moreover, the presented watermark protocol does not rely on any image transform algorithm, so it is easy to analyze the computational complexity. According to the given quantum circuits, this paper analyzes the computational complexity of the presented protocol.