Study On Image Information Hiding Algorithm Based On Spatial Domain

With the rapid development of internet technology and multimedia technology, the communication of multimedia information becomes more and more convenient and swift. People can send and receive much media information without any limitations of time and space, but, information security is also facing new challenges simultaneously at the same time. Information hiding technology as an important means of protecting information security has been widely researched.Through the researches and analysis on the principle of image information hiding and the existing hiding methods, aiming at the shortage of hiding capacity is small in frequency domain and different application requirements of hiding technology, two new digital image information hiding algorithms are proposed in this paper.Therein, the hiding algorithm based on improved bilinear interpolation firstly preprocess the original images by means of the improved bilinear interpolation to re-interpolate the points which the secret information embedded in, so as to create more redundant space for hiding secret information to increase the hiding capacity. Then, using the thoughts of changing difference of two adjacent gray values, and adopting mathematical methods to achieve information hiding.Furthermore, in view of the original image is as important as secret image in some special fields, thus the original image should be fully restored after extracting secret image. However, the original image hiding secret image would be resulted in irreparable destruction by traditional information hiding algorithm, therefore, this paper proposes a new kind of lossless data hiding algorithm based on spatial domain. This method uses the method of hiding "index file" to achieve the purpose of lossless information hiding. In the embedding process, inspired by the method of histogram shifting, using simple math calculation to embed information layer by layer, and adopting different block modes and different calculation methods in odd layers and even layers, so as to realize a large number of secret messages hidden under the premise of guaranteeing image effectively.Through computer simulation experimental analysis about various performances of the two algorithms such as hiding capacity, fidelity, statistical properties and cropping attack, it is indicate that both algorithms can maintain a higher peak signal to noise ratio when guarantying a certain hiding capacity, and also can resist statistical analysis and cropping attack effectively. All the above prove that these two algorithms are secure and reliable. At the end of the thesis the future research direction information hiding is forecasted.