为提高隐秘通信的安全性和效率，将图像编码和图像拼接相结合，提出了一种基 于图像编码及拼接的无载体信息隐藏算法． 在对图像编码时，首先对图像进行分块，求取 每一子块的信息熵，形成熵矩阵并对其进行量化编码，构建图像与随机数间的映射关系; 在进行图像拼接时，对要表示的随机数进行分组，从完备图像库中选出对应的图像，并按 一定的位置关系进行拼接，将拼接后的图像作为含密载体进行传递，以提高单次通信效 率;为减少通信中的误码率，算法还对秘密消息进行 CＲC 循环编码． 实验结果表明，文中 算法具有良好的抗检测分析性能、良好的抗压缩攻击和抗椒盐噪声攻击能力，在安全级别 高、隐藏容量不大的隐秘通信中具有重要的应用价值． 

In this paper，a coverless information hiding method is introduced on the basis of image coding and splicing in order to improve effectively the security and efficiency of covert communication． Firstly， the image is divided into blocks，and the entropy of each block is calculated to construct an entropy matrix． The entropy matrix is quantized and then the mapping relation is constructed between the random number sequence and the image feature． Secondly， the random number sequence to be represented is divided into segments，and the correct images are extracted from the complete image database corresponding to the information segments． Finally，those selected images are spliced with a certain positional relationship． In this way，the stitching image is a secret carrier for transmission，which makes a high-efficiency covert communication with a coverless information hiding． Besides， the secret information is encoded with CＲC codes to improve the security． The experimental results show that the proposed algorithm has great tolerance of JPEG compression attack and salt ＆ pepper noise attack，and has a good performance of antisteganalysis． This method is significantly valuable in applying covert communication with low capacity and high security．