Abstract:

In recent years,the chaosbased image encryption technique is developed as a new approach.But onedimensional,twod or threed integral chaos systems are usually used,few people apply a fractional order chaotic system. We compare the fractional Duffing system with the integral Duffing system in key spaces and pseudo random sequences. Theoretical analyses and computer simulations both confirm that the chaotic sequences of the fractional system is more random. The order number of the fractional system also can be applied as key. So, in theory, the key space of a fractional Duffing system is bigger than that of an integral Duffing system. In conclusion, the fractional Duffing system is more suitable for image encryption,and the encryption results is good.

Key words: chaos；fractional Duffing；pseudo random；image encryption