Research On Digital Image Encryption Based On DNA Sequence And Multi-chaotic Maps

The computer network has changed the mode of people's communication; people can easily transfer several of multimedia information through the network. However, since the openness of the network, the security of multimedia information has been threatened. The digital image is an important information vector of multimedia communication, thus how to protect the image information becomes an universal concern problem for people. At present,image encryption is one of most effective means to protect the safety of image information.The major works of this paper includes the following parts:1. In the paper, we describe the research value and significance of digital image encryption at first, and introduce the existing image encryption schemes; then the DNA cryptography theory and the chaos theory are introduced in detail. In order to overcome the shortcomings of the existing schemes based on chaotic maps and based on DNA cryptography, in this paper, we proposed three image encryption schemes based on DNA sequence and multi-chaotic maps.2. A new image encryption algorithm based on DNA sequence and multi-chaotic maps is presented in this paper. First, by using Cubic map and wavelet function to produce the 2D chaotic sequences to scramble the location of pixel points from the image. Second, select DNA encoding map rule by using a random number to encode the scrambled image. Then, to disturb the gray of the pixel points from image by using the Logistic map generate a chaotic sequence and DNA sequence. At last, select DNA decoding map rule by using another random number to decode the DNA sequence, in the way, the encrypted image are obtained.3. An image fusion encryption algorithm based on DNA sequence and multi-chaotic maps is presented. Firstly, the original image and the key image are encoded into two DNA sequences matrices. Secondly, by using Cubic map and wavelet function to produce the 2D chaotic sequences to scramble the location of these two DNA sequences matrices. Then, add these two scrambled coding matrices according to DNA adding operation, the added matrix is obtained. Thirdly, carry out DNA sequence complement operation by using Logistic map for the added result matrix. At last, decode the result from the third step; we will gain the encrypted image.4. A novel image encryption algorithm based on DNA subsequence operation is proposed. In this algorithm, the original image is converted into several DNA subsequences, at first. Then, to disturb the position and the value of pixel points from image by combining the Logistic map generate chaotic sequences and DNA subsequence operations (such as elongation operation, truncation operation, deletion operation, transformation, etc.). At last, the encrypted image is obtained by DNA decoding and recombining bit-planes.It has carried out simulation experimental and security analysis for each algorithm, and compared with the existing encryption schemes. The results of experiment and comparison show that these proposed algorithms can get good encryption effect, have a wide secret key's space, strong sensitive to secret key, and have the ability of resisting exhaustive attack and statistic attack. In addition to that, the security of encryption system will be determined by chaotic systems and DNA computing biological knowledge, which is equivalent to that,the encryption system has the double insurance.