针对空域明文LSB隐写的消息提取方法

Message extraction method for plaintext LSB steganography in spatial domain

在嵌入消息为明文的情况下,利用中英文字节比特的统计特性,改进了已有的针对空域连续最低有效位(LSB)隐写的消息提取方法,提高了提取消息的准确度;提出了一种针对空域随机LSB隐写的消息提取方法.该方法首先求出恢复隐写密钥的唯一解距,然后穷举隐写密钥空间,对每个密钥确定长度为T的隐写路径,提取此隐写路径上像素的LSB,并从该LSB序列的第一个比特开始间隔7采样获得一条子序列,若该子序列为全0或全1,则该密钥为真密钥,否则为伪密钥;同时还研究了漏检的情况.实验结果表明了本文方法的可行性和有效性.

Under the condition of plaintext,by using the bit′s statistical property of both English and Chinese words,a message extraction method for the sequential LSB（least significant bit）steganography in spatial domain was promoted and the extraction message accuracy was improved.Next a message extraction method for the random LSB steganography in spatial domain was put forward.Firstly,the unicity distance was obtained to recover the stego key;secondly,by stego key exhaustive searching,each stego key′s steganographic path was determined and the LSB was extracted with the length of T;thirdly,a new subsequence was gained with the first bit of the LSB as the beginning and 7sampling interval,and the true stego key could be determined if the subsequence was the sequence of all zeros or all non-zeros.Besides,the leak detection was also studied.The experimental results have proved the feasibility and effectiveness of the method.