摘要：Encryption algorithm of traditional cryptology has strong safety, but the effect of encrypting images is not good. Digital image scrambling means that a digital image is transformed into a chaotic image which has no evident significance, but the operator can reconstruct the chaotic image into the original image by using the specific algorithm. Image scrambling encryption technology based on chaos theory makes use of chaotic signal to encrypt image data flow, which has the advantages of high safety, rapid encryption speed, large key space and good scrambling effect. The paper studies invalid-key and quasi invalid-key existed in chaotic sequence which is generated by Logistic map, and proposes image scrambling encryption algorithm based on mixed and chaotic sequence. The algorithm has a good robustness for the JPEG compression with the fixed coefficient, and a good fragileness for the illegal manipulation.
