Zhu Shuqin, Zhu Congxu, Wang Wenhong
School of Computer and Science, Liaocheng University, Liaocheng 252059, China.
School of Information Science and Engineering, Central South University, Changsha 410083, China.
Entropy (Basel). 2018 Sep 19;20(9):716. doi: 10.3390/e20090716.
In order to overcome the difficulty of key management in "one time pad" encryption schemes and also resist the attack of chosen plaintext, a new image encryption algorithm based on chaos and SHA-256 is proposed in this paper. The architecture of confusion and diffusion is adopted. Firstly, the surrounding of a plaintext image is surrounded by a sequence generated from the SHA-256 hash value of the plaintext to ensure that each encrypted result is different. Secondly, the image is scrambled according to the random sequence obtained by adding the disturbance term associated with the plaintext to the chaotic sequence. Third, the cyphertext (plaintext) feedback mechanism of the dynamic index in the diffusion stage is adopted, that is, the location index of the cyphertext (plaintext) used for feedback is dynamic. The above measures can ensure that the algorithm can resist chosen plaintext attacks and can overcome the difficulty of key management in "one time pad" encryption scheme. Also, experimental results such as key space analysis, key sensitivity analysis, differential analysis, histograms, information entropy, and correlation coefficients show that the image encryption algorithm is safe and reliable, and has high application potential.
为了克服“一次性密码本”加密方案中密钥管理的困难，并抵抗选择明文攻击，本文提出了一种基于混沌和SHA - 256的新型图像加密算法。采用了混淆和扩散结构。首先，明文图像的周边由从明文的SHA - 256哈希值生成的序列包围，以确保每个加密结果都不同。其次，根据通过将与明文相关的干扰项添加到混沌序列中获得的随机序列对图像进行置乱。第三，采用扩散阶段动态索引的密文（明文）反馈机制，即用于反馈的密文（明文）的位置索引是动态的。上述措施可以确保该算法能够抵抗选择明文攻击，并能够克服“一次性密码本”加密方案中密钥管理的困难。此外，诸如密钥空间分析、密钥敏感性分析、差分分析、直方图、信息熵和相关系数等实验结果表明，该图像加密算法安全可靠，具有很高的应用潜力。
