目的 随着存在大量低性能电子设备的物联网系统迅速发展和普及，人们对低精度计算环境下安全高效的图像加密技术有着越来越迫切的需求。现有以混沌系统为代表的图像加密方法不仅加密速度普遍较低，而且在低精度计算环境下存在严重的安全缺陷，难以满足实际需求。针对上述问题，本文提出了一种基于素数模乘线性同余产生器的批图像加密方法，用以提升低精度环境下图像加密的效率和安全性。方法 该方法的核心是构建一个能在低精度环境下有效运行的素数模乘线性同余产生器；将图像集均分为3组，并借助异或运算生成3幅组合图像；接着引入图像集的哈希值更新上述第3组图像；将更新后的组合图像作为上述产生器的输入，进而生成一个加密序列矩阵；基于加密序列矩阵对明文图像进行置乱和扩散，并使用异或运算生成密文图像；使用具有较高安全性的改进版2D-SCL （a new 2D hypher chaotic map based on the sine map，the chebysher map and a linear function）加密方法对加密序列矩阵进行加密。结果 仿真结果表明，本文提出的批图像加密方法在计算精度为2^－8的情况下不仅能抵御各类攻击，而且加密速度相较于对比加密方法有所提升。而对比加密方法在上述计算精度环境下存在不能抵御相应攻击的情况。结论 本文提出的基于素数模乘线性同余产生器的批图像加密方法，不仅有效地解决了低计算精度环境下图像加密安全性低的问题，而且还大幅提升了图像的加密速度，为后续高效安全图像加密方法的研究提供了一个新的思路。

Objective Digital image has the ability of intuitive and clear information expression, and always carries a lot of valuable information. Therefore, the security of digital image is very important. With the rapid development and popularization of internet of things (IOT) which contains a large number of low-performance electronic devices, and the demand of security and efficient image encryption method in low computing precision environment is becoming more and more urgent. Recently, the chaos-based encryption system is the kind of most representative image encryption method. This type of encryption method depends on float operations and high computing precision. Therefore, the randomness of these chaotic systems in low computing precision will be severely damaged, and results in a sharp decrease about the security of the corresponding encryption method. Moreover, the high time complexity always causes the chaos-based image encryption methods to failure to meet the actual demand of low performance device. To solve the above problems, this paper proposes a batch encryption method based on prime modulo multiplication linear congruence generator to improve the security and efficiency of image encryption in low computing precision environments. Method The main idea of the method is to construct a prime modulo multiplication linear congruence generator, which can work well and generate a uniformly distributed pseudo-random sequence at low computing precision. The main steps are as follows:firstly, the set of images are equally divided into three groups and each group generates one combined image based on XOR operation; secondly, the hash value of the set of images is introduced to update the third combined image; thirdly, we introduce a single-byte based prime modulo multiplication linear congruence generator, the updated combined image and the other two combined images are used as the input of the proposed generator to generate an encryption sequence matrix; then the encryption sequence matrix is used as parameter to scramble images; after that, the encryption sequence matrix is exploited to diffuse the scrambled images, and use XOR operation to generate cipher images; finally, the encryption sequence matrix would be encrypted by the improved 2D-SCL which is the existing state-of-art encryption method, thus the cipher images and encrypted sequence matrix can be safely transmitted. Result The proposed encryption method has been evaluated by simulation tests in low (2^-8) computing precision surroundings. The simulation results show that the statistical information of cipher image are very good in low precision environment, such as low correlation (close to 0), high information entropy (close to 8) and high pass rate of number of pixel changing rate(NPCR) and unified average changed intensity(UACI) which are greater than 90%. In addition, the simulation results also show that the proposed encryption method works well on many attacks in low precision environment, such as high pixel sensitivity, large key space (more than2¹²⁸), and high resistance of known-plaintext and chosen-plaintext attack, occlusion attack and noise attack. Moreover, the encryption speed of this method is improved compared with the comparative encryption method which has low time complexity. Conclusion The proposed method can be effectively operated in low computing precision environment by using the single-byte prime modulo multiplication linear congruence generator instead of chaos system. As simulations results shown that the proposed method not only achieves high security for image encryption in low computing precision environment, but also effectively reduces the time cost of image encryption. In addition, the proposed method also provides a new direction for subsequent research of efficient and security image encryption method.