Abstract: Many people apply the low-dimension chaotic map to encryption,however,the high-dimension map is more complex and has more parameters.Firstly,a 4-dimensional generalized chaotic synchronization (GCS) system was constructed based on generalized chaotic synchronization theorem.Combining this system,we designed a digital image encryption scheme,which can successfully encrypt and decrypt color images without any distortion.Secondly,performance test and security analysis were performed by using key space analysis and the pixels distribution character,correlation coefficients,the key sensitivity test,information entropy and avalanche effect. The results of analysis and simulation show that the key space of the image encryption scheme is more than 10²⁸⁸ and it has strongly anti-attacking perfor-mance. Additionally,the scheme is extremely sensitive to the system’s parameters and initial conditions.Results suggest that the image scheme is effective in network communication.

Key words: Secure communication,Image encryption,Generalized chaotic synchronization