Abstract: The 1D chaotic image encryption method is reported with appropriate performances by using the appropriate complexity，pseudo-randomness and extreme parameter sensitivity of chaotic sequences but with smaller key space as its serious drawback compared with others.So，a new image encryption method based on 3D chaotic system is proposed in this paper，which can not only increase secret key space，but also tone up ability to deciphering.And in this paper，the pixel value of cipher-image used to get secret key and the feedback used in encryption process improve greatly the performances of the diffusion function.The method is proved to work well by the result，because of its larger secret key space and high speed of encryption and so on.

Key words: 3D chaotic system, chaotic sequence, image encryption

摘要： 一维混沌加密算法由于利用了混沌序列的良好复杂性、伪随机性和对初值的敏感特性而具有较好的加密性能，但与其它方法比较，其缺点是密钥空间较小。为此，提出了一种基于三维混沌系统的图像加密新方法，扩大了密钥空间，提高了加密系统的抗破译强度。通过在密钥发生器中嵌入密文像素值，在加密过程中引入反馈加密法，使得扩散函数的影响得到了进一步的加强。实验结果表明，算法具有密钥空间大，加密速度快及效果好等优点。

关键词: 三维混沌系统, 混沌序列, 图像加密