An Improved Image Scrambling Algorithm

Image unchangeable coefficient rule in discrete cosine and wavelet transformation was proved when it was scrambled in spatial domain. Based on the constructed composite chaotic iterative dynamic system, whose invariant distribution density was one, and in order to initialize for composite chaotic iterative dynamic system, it put forward two construced functions using image scramble constant as input parameter. Then a fragile and adaptive image scrambling algorithm and two new scrambling evaluative parameter were brought forward. They were called similar degree and anti-tamper radius. Experiments showed that the algorithm could extract original image without any accessional information, it was sensitive to all kinds of attack, its anti-tamper radius was larger than current scrambling algorithms. So the algorithm could be applied to the situation of the strictest requests, such as lawcourt and physic etc.