Realization Of Image Hiding Algorithm Based On The Chaotic Encryption And Wavelet Transform

Chaos system is regarded as a kind of natural password system. Due to its sensitivity, ergodicity and determinacy to initial extreme, it is considered as a very promising encryption algorithm to combine the chaos and existing encryption algorithm. But the charactertistics of irregularities of chaos in two-dimensional phase plane provides an effective way to seek more suitable image data encryption method. Wavelet transform is a time-frequency analysis method which can achieve part of time or frequency, the basic idea is to separate the frequency signal, that is multiresolution decomposition. Wavelet transform has multiresolution analysis ability ,it is more adaptive to the visual characteristics, which can effectively resist the lossy compression of JPEG2000. It can also disperse secret image to the multiple dimensions of image. Thus based on wavelet transform hidden information algorithm has the characteristics of invisibility and high robustness. Based on chaotic image encryption and based onwavelet transform image hiding technology have each of their merits and demerits, these two methods should be complemented and combineded organically, which can further enhance image information security.Logistic mapping is a typical nonlinear chaotic equation, it operation simple, and it has good chaos characteristics. But the key space is limited, use the tectonic encryption algorithm safety is not high. This paper by increasing the number of parameters in mapping to expand the key space, at the same time to ensure that encryption algorithm design as far as possible on the simple, proposed based on single Logistic mapping image encryption algorithm, using additional parameters generated by the chaotic sequence for different transformation, obtain scrambling encryption and alternative encryption matrix, and to realize the image information of the double substitution scrambling encryption processing. The algorithm to a certain extent overcome the Logistic few parameters, the key space limited defects, through different parameters and transform obtain scrambling and alternative matrix, avoid computing multiple sequences to generate the corresponding transformation matrix, reduced the algorithm computational cost. In hidden secret image before, the original secret image preprocessing chaotic encryption, can improve image hidden invisible and robust, combining based on wavelet transform image hiding technology, this paper finally proposed based on chaotic encryption and wavelet transform image hiding algorithm. Due to limited by computer to realize precision chaotic sequences existing characteristics degradation problems, use "ordinary key" and "to ordinary key" as a single Logistic mapping encryption system parameters can be used to encrypt when do not produce chaotic sequences, so for based on single Logistic mapping image encryption algorithm and improved, this paper presents a new method based on double Logistic mixed mapping image encryption algorithm, and applied to secret image encryption processing, and then put the encrypted secret image hiding to carrier images by wavelet decomposition after, and pass band coefficient of the reconstruction of wavelet get secret image. The algorithm is simple, easy to realize determinately etc. Characteristics. The simulation results show that the proposed algorithm suffers JPEG compress, noise and cutting etc image processing conditions, robustness.