Abstract: Dictionary-steganograhpy is a method using texts to hiding secret information, which transforms secret message directly into stego-text similar to ordinary text using a dictionary. This paper analyzes the statistical characteristics and finds the differences of the stego-text and natural lingual text by modeling the latter, which shows frangibility of the traditional algorithm. The paper improves the dictionary of the algorithm, which makes the stego-texts similarly to natural texts on familiar statistical characteristics. This improvement makes up the shortages and improves the security of the traditional algorithm.

Key words: steganography, dictionary, text, steganalysis, statistical characteristics, frangibility

摘要： 字典隐藏法是一类基于文本的信息隐藏方法，它利用用户字典将秘密消息直接变换生成结构与普通文本相似的隐密消息。该文通过对自然文本进行建模，分析隐密文本与自然文本的统计特征，得到其中的差异，证明了字典隐藏法存在一定的脆弱性。对传统字典法的用户字典加以改进，使得隐藏后得到的隐密文本与自然文本在常用统计特征上并无异样，弥补了传统字典法的不足，提高了算法的安全性。

关键词: 隐藏, 字典, 文本, 隐写分析, 统计特征, 脆弱性

CLC Number: 

• TP391