基于双向扩散机制融合伪随机数同步生成器的快速图像加密算法研究

针对当前混沌加密系统普遍了采用单向扩散机制进行加密,导致了较低的计算效率和加解密速度,在面对高解析度、大容量图像时,无法满足安全、实时性等缺陷,设计了一种双向扩散机制和伪随机数同步生成器,提出了基于双向扩散机制与伪随机数同步生成器的图像加密算法;并与传统的加密机制进行了对比分析。通过伪随机数同步生成器将256 bit长的外部密钥同步生成加密算法的初始条件和控制参数,并进行迭代计算超混沌系统,得到一组超混沌序列;然后用位置集合置乱方法置乱该序列,得到一个位置集合,用该集合置乱图像;最后采用密钥流机制量化超混沌序列,通过双向扩散机制加密图像。借助MATLAB仿真实验来测试该算法,结果显示具有理想的加密质量,加密机制高度安全,密钥空间足够大;较传统的扩散机制而言具有很高的计算效率,加密速度快,可满足实时传输要求。

The Research of Fast Image Encryption Algorithm Based on Bilateral Direction Diffusion Mechanism Integration with Synchronized Pseudo-random Number Generator

To defects such as the low speed of encryption and decryption, as well as the low computation efficiency induced by the single diffusion mechanism in the current chaotic-based encryption system, and can not satisfy the security and real-time transmission when in the face of high resolution, large capacity image. So a bilateral direction diffusion mechanism and synchronized pseudo-random number generator were designed in this paper to propose the fast image encryption algorithm based on bilateral direction diffusion mechanism integration with synchronized pseudo-random number generator to solve above problems, and the comparative analysis was done with the traditional diffusion mechanism. The initial conditions were produced by the external key of 256 bites under the synchronized pseudo-random number generator to iterate the hyper-chaotic system for getting one group hyper-chaotic sequence; then the permutation method of position set was used to permute the pseudo-random sequence to get one position set, and used it t to permute the image; Finally, the key stream mechanism was used to treat the hyper-chaotic pseudo-random sequence, and use the double-direction diffusion mechanism to encrypt image. The MATLAB simulation software was used to validate the method proposed by this paper, the results showed that the image encryption algorithm in this paper had better encryption performance, the key space is larger, the anti-plaintext attack property was greatly enhanced; comparing with the traditional diffusion mechanism, the encryption algorithm in this paper had a high computational efficiency and high encryption speed to meet the requirement of real-time transmission.