一种基于像素块的纹理优先自适应隐写算法

A Pixel Block-Based Adaptive Steganographic Algorithm with Embedding Priority Given to Image Textures

与平坦区域相比,图像纹理区域在结构上表现出更多的随机性,因此将密信嵌入到纹理丰富的区域可获得更好的安全性.本文利用相邻像素的LSB与次低LSB位之间的关系,提出一种基于像素块的纹理优先自适应隐写算法,将密信优先嵌入到复杂纹理区域.所设计的纹理判别准则能结合待嵌入密信长度,自适应选择嵌入区域.针对在嵌密过程中嵌密块可能出现的异常情况,提出一种像素值调整方案,并从理论上证明了其可行性.实验结果表明本文算法比两种经典的LSB算法和一种现有的基于边缘优先的自适应算法具有更高的嵌入效率,且对四种有代表性的隐写分析算法通常具有更强的抵御能力.

Compared with flat regions,image textures have more randomness in structure. As a result,the embedding of secret message in rich textures can obtain better security. Based on the relationship between the least two significant bits of neighboring pixels,we propose a pixel block-based adaptive steganographic algorithm with embedding priority given to image texture regions. In other words,the embedding order is from rich textures to flat regions. Our criterion for texture assessment can adaptively allocate image regions for embedding according to the length of the secret message. To deal with possible irregular embedding blocks,we propose a pixel value modification solution. We have justified this solution mathematically. Experimental results have demonstrated that our algorithm outperforms two established LSB（ least significant bit） embedding algorithms and one current edge adaptive steganographic algorithm in terms of embedding efficiency; meanwhile,our algorithm often has stronger resistance to the four representative steganalytic algorithms.