基于混沌系统与多方向扩散的图像加密算法

目的为了避免只从单一方向来扩散图像像素,并提高加密密文的安全性,设计了混沌系统与多方向连续扩散的图像加密算法。方法综合Tent,sine映射,联合改进的Logistic映射,设计混合混沌机制,将Logistic模型的输出值作为触发器,获取一组随机性较强的混沌序列,对初始明文进行交叉置乱,高度混淆其像素位置,有效降低置乱周期性;构建量化机制对混沌序列进行处理,获取密钥流,从而设计多方向连续扩散机制,从4个不同的方向,利用不同的扩散模型来改变像素值,显著降低扩散周期性。结果实验结果显示,与当前混沌加密机制相比,所提算法具有更高的安全性与敏感性。结论所提加密算法能够确保图像在网络中安全传输,在包装信息防伪等领域具有较好的应用价值。

Image Encryption Algorithm Based on Chaotic System and Multi-direction Diffusion

The work aims to design an image encryption algorithm based on chaotic system and multi-direction continuous diffusion for the purpose of preventing the diffusion of image pixel in a single direction and improving the security of encrypted cipher. Firstly, with the output value of Logistic model as the trigger, the mixed chaotic mechanism was designed in combination with Tent map, Sine map and improved Logistic mapping to obtain a set of chaotic sequences with strong randomness for scrambling the initial plaintext to highly confuse the pixel position and effectively reduce the scrambling periodicity. Then, the quantization mechanism was constructed to deal with chaotic sequences for obtaining the key-stream; and the multi-direction continuous diffusion mechanism was designed to change the pixel values from 4 different directions with different diffusion models, thus reducing the diffusion periodicity remarkably. The experimental results showed that the proposed algorithm had higher security and sensitivity compared with the current chaotic encryption mechanism. The proposed encryption algorithm can ensure the secure transmission of images in the network, and has better application value in packaging information anti-counterfeiting and other fields.