Research Of Encryption Algorithm Based On Digital Image Information Hiding And Mixed Chaos Sequences

Cryptography has a long history, It is a major had three great periods of development. The first period :Hand stage, is primarily through the artificial strings can be encrypted. The second period: machine period, after the industrial revolution. With the cipher produced, the means to create more fine and complicated, but also improve efficiency. but in this period of theories have not much changed, the main methods are substitution and empathic. The third period: modern cryptography period, the computer has made many highly complex operation can be operated, so cryptography get more vigorous development. Now many countries have done a highly thorough research and development in modern cryptography. Modern cryptography combine with many aspects of science. Such as physical, Quantum Mechanics, electronics and linguistics. "Chaos encrypted," "language encrypted" and other advanced theories play an important role in cryptography security.This paper the first to introduce chaotic development of theory and chaos theory of knowledge and related theory; discussed 1-D logistic map and it's shortage, on this basis, we introduce multi initial values 2-D logistic- map, the complexity and periodic of chaotic system is greatly improved. After researched on some image scrambling algorithms, this paper introduce the improved sequence cross method, the method have high speed and good scrambling effectiveness. and the method to avoid cross sequence circulating reduction .In this paper, first the carrier image was encrypted using mixed chaotic sequence, to hide the distribution characteristics of carrier image, and get the encryption key, but it reserves the characteristics of the chaos dynamics. And the plaintext be encrypted by mixed chaotic system, it also reserve characteristics of the chaos dynamics, so the secrecy of encryption is not very high. To this shortage, this paper introduce a new method, using encryption image to hide the first level cipher text information. To destroy the cipher text characteristics of the chaos dynamics, thereby making its confidentiality can be greatly improved. The experimental results show that this designer :initial values sensitivity, the histogram even distribution of pixels, correlation between adjacent pixel, the length and strength of decryption key are greatly improved.