基于超混沌系统的多图加密算法

针对现存混沌图像加密算法中，存在系统安全性不高、无法抵御明文攻击、加密图像相互独立、效率低等问题，提出了一种基于超混沌系统的多图加密算法。利用超混沌系统产生性能优良的混沌伪随机序列，并将多幅大小相同的图像拼合为一幅图像，之后采取一系列新颖的加密操作完成图像加密过程。此算法引入明文干扰项，采用比特级别的行列置乱、DNA随机编码、DNA的快速置乱与扩散操作，解密时可以自动检索干扰项，不仅使算法摆脱了一次一密(one-time pad,OTP)模式，而且使得混沌随机序列可以安全重复地使用。仿真结果表明，算法可以大幅度减少混沌序列的迭代次数，同时也保证了图像之间的高度关联，能够掩盖明文的比特信息分布，具有较高的明文敏感性，满足图像加密的基本要求。

Multi-image encryption algorithm based on hyper-chaotic system

Among the existing chaotic image encryption algorithms, there are problems such as low system security, inability to resist plaintext attacks, independent of encrypted images, and low efficiency.A multi-image encryption algorithm based on the hyper-chaotic system is proposed.The hyperchaotic system is used to generate chaotic pseudo-random sequences with excellent performance, and multiple images of the same size are combined into one image. Then a series of novel encryption operations are taken to complete the image encryption process.This algorithm introduces plaintext interference terms and involves bit-level rows and columns scrambling,the randomization of DNA,and fast scrambling and spreading operation of DNA. The interference term can be automatically retrieved during decryption with avoidance of the OTP(one-time pad) mode, which makes chaotic random sequences safe and reusable. The simulation and analysis show that the iteration times of chaotic sequences are reduced, the high correlation between images is ensured and the distribution of bit information in plaintext is hidden. The algorithm has good security and can meet the basic requirements of image encryption.