Technol Health Care. 2020;28(S1):303-309. doi: 10.3233/THC-209030.
The chaotic system with low dimensions has a low security compared to the high-dimensional chaotic system. Furthermore, major pixel-level permutations merely transform the pixel position and cannot change the intensity distribution of the original image. Bit-level permutation could change the intensity distribution, as it devotes more time to conduct bit-level computation.
In this study, we present a more efficient image encryption approach based on hyper-chaos and a global bit cycle shift (HC-GBCS).
According to the input image we adopted the SHA-256 secure hash algorithm to obtain the initial key, which served as the premier parameter of the chaotic system. Then we employed a 4D hyper-chaotic system for generating the chaotic series, on which we utilized global bit permutation to enhance the security of the encryption system. Finally, the diffusion process was conducted by using the generated chaotic series extended with a logistic map.
Experimental results and analysis reveal that the presented approach encrypts plain images effectively and achieves high security and stability.
The proposed method can deal with the problems inherently existing in encryption methods utilizing low-dimensional chaotic map. Furthermore, global bit permutation can transform the pixel distribution of plain images and enhance the cryptosystem security.
与高维混沌系统相比，低维混沌系统的安全性较低。此外，主要的像素级置换仅改变像素位置，无法改变原始图像的强度分布。位级置换可以改变强度分布，因为它需要更多的时间进行位级计算。
本研究提出了一种基于超混沌和全局位循环移位（HC-GBCS）的更有效的图像加密方法。
根据输入图像，我们采用 SHA-256 安全哈希算法获得初始密钥，作为混沌系统的主要参数。然后，我们使用 4D 超混沌系统生成混沌序列，并利用全局位置换增强加密系统的安全性。最后，通过使用生成的混沌序列扩展的 logistic 映射进行扩散过程。
实验结果和分析表明，所提出的方法可以有效地对明文图像进行加密，并实现高安全性和稳定性。
所提出的方法可以解决使用低维混沌映射的加密方法中存在的固有问题。此外，全局位置换可以改变明文图像的像素分布，增强密码系统的安全性。
