Abstract: This paper proposes an image encryption method based on spatiotemporal chaos.Firstly，the balance of the pseudorandom sequences produced by two way coupled map lattice model is researched and improved.Then，the image key and the external key，which can resist an exhaustive attack and a known-plaintext attack，are proposed.Finally，the whole encryption process is realized by the confusion of the image pixels’ values and the permutation of the pixels’ positions.The security analysis shows that the method has very good encryption effect.

摘要： 研究并改进了双向耦合映像格子模型所产生伪随机序列的平衡性。设计了加密系统的密钥结构，可有效地抵御蛮力攻击和已知明文攻击。通过图像像素值的扰乱和像素位置的置乱来实现加密并对算法进行数字仿真和安全性分析。实验结果和理论分析表明算法具有良好的加密效果、较高的安全性和较高的密钥敏感性。