Study On Quantum Algorithm For Image Watermarking And Encryption

Today’s society is an information society. Information’s safety related to the national security and national interests as a strategic resource. Therefore, how to ensure the security of information has become an important research topic for scholars. Cryptography which is the core technology of information security play an important role in modern communications. However, with the rapid increase in computing power of mankind, especially the proposed quantum parallel algorithms, the security of classical cryptographic protocols based on computational complexity is seriously challenged. Against this background that scholars are eyeing up quantum cryptography.Quantum cryptography is a combination product of cryptography and quantum mechanics. Its safety is ensured by the basic principles of quantum mechanics and has nothing to do with the attacker’s computing power, so it can achieve unconditional security. Theoretical study and experimental results show that quantum cryptography is likely to become an important force in the next generation of cryptographic techniques.Multimedia object is currently widely used by Internet, how to protect their security will become a leading subject in quantum information age. This chapter carried out the works on the image security in quantum cryptography list in the following:(1)Song et al. proposed a dynamic watermarking scheme foe quantum images using quantum wavelet transform. By analyzing, we found the watermark embedding and extracting procedures of the protocol are incorrect. For this, we presented a possible improvement strategy.(2)Because conventional hash functions need more complicated computations, the chapter proposed a quantum hash function scheme based on quantum random walk(QW). We proved the chaotic dynamics of QW, and constructed the hash function based on the chaotic dynamics later. Then we did some security test on the hash function such as sensitivity test, statistical analysis of diffusion and confusion and so on which can preliminary proof that the hash function is available to a certain extent. It can effectively resist statistical attacks and force attacks.(3)This paper constructed a pseudo-random number generator(PRNG) based on quantum hash function and did some test on the output of this PRNG such as statistical complexity measure, Degree of non-periodicity test, Recurrence plots test and so on which can proof that the PRNG has a goof performance in randomness and uncertainty. Further we proposed a novel image encryption algorithm based on this PRNG. We did the numerical simulations and performance comparisons. In this paper, we did the histogram test, correlation test, sensitivity analysis and key sensitivity test respectively, the results proved the security of the encryption scheme.