Chaos and cryptography have some common features, such as sensitivity to variables and parameters change. Many fundamental characteristics of chaos, such as the ergodicity and mixing property and the sensitivity to initial conditions can be connected with the "confusion" and "diffusion" property in cryptography. A combination between cryptosystems realized in analog circuits and conventional cipher has been made by using the AES as the encryption and decryption rule in the chaotic cryptosystem based on chaos synchronization techniques. The proposed algorithm has been simulated and applied in encrypting and decrypting images. The results show that encrypted data have passed all statistical tests and the confusion and diffusion properties have also been demonstrated by testing the histograms of the ciphered images and calculating the amount of correlations between the adjacent pixels in the ciphered image.