CAJ | 학술논문

针对同义词替换操作造成原始文本整体统计特性的破坏，提出了一种基于低失真替换优先的文本隐写算法。该算法以同义词在文本中的合适度为基础，构造失真函数衡量同义词替换后文本统计特性的改变程度；不仅为每个同义的词集合选取合适度最高的两个词组成替换组合，而且从全局的角度出发，对原始文本中的所有同义词替换组合所引起的失真度进行排序，优先选取失真度小的同义词替换组合来嵌入信息，从而降低了同义词序列统计特性的改变程度。实验结果表明，该算法可以很好地抵抗基于同义词结对和基于同义词相对词频统计特征的隐藏信息检测算法的攻击，具有较高的抗检测能力，提高了秘密信息的安全性。
침대동의사체환조작조성원시문본정체통계특성적파배，제출료일충기우저실진체환우선적문본은사산법。해산법이동의사재문본중적합괄도위기출，구조실진함수형량동의사체환후문본통계특성적개변정도；불부위매개동의적사집합선취합괄도최고적량개사조성체환조합，이차종전국적각도출발，대원시문본중적소유동의사체환조합소인기적실진도진행배서，우선선취실진도소적동의사체환조합래감입신식，종이강저료동의사서렬통계특성적개변정도。실험결과표명，해산법가이흔호지저항기우동의사결대화기우동의사상대사빈통계특정적은장신식검측산법적공격，구유교고적항검측능력，제고료비밀신식적안전성。
As overall statistical characteristics of the cover text would be changed in the process of synonym substitutions, this paper proposes a text steganographic algorithm using the prior substitutions with low distortion. Taking the suitability of synonyms in the context into account, the proposed algorithm constructs a distortion function to measure the degree of the statistical characteristics changed by synonym substitutions. It not only selects two words with the highest suitability from each synonymous word set to form a substitution set, but also from the global perspective, gives priority to the substi-tution sets with low distortions to be embedded secret information after sorting the distortions caused by all the substitution sets in the cover text. Therefore, the changed degree of the statistical characteristics is reduced. The experimental results show that the algorithm can effectively resist the attacks made by detection algorithms using statistical features based on the synonyms pairing and relative frequency. The proposed algorithm has a good resistance to detection, and can improve the security of the secret information.