分级安全的文本隐写方法

针对单一数据类型隐写方法安全性不高、隐写容量不足等问题,提出了一种具有分级安全的文本隐写方法。首先,将整个载体文档中的多种类型的数据作为备选隐写载体,以不同类型数据的隐写特点和隐写分析技术为评估依据定义隐写安全等级,构建了一个多类数据融合的分级安全隐写模型。然后,根据秘密信息的长度自适应确定安全等级,并利用分级安全隐写模型将秘密信息分块地嵌入在同一个载体文档相互独立的多个不同类数据中。理论分析及实验结果表明,与现有基于单一数据类型隐写方法相比,所提方法扩大了隐写容量,在嵌入等量的秘密信息情况下,降低了文档中同一类载体数据的统计特征改变程度,提高了秘密信息的整体安全性。

Text steganographic method with hierarchical security

For the low security and capacity shortages of steganographic methods based on the single data, a new text steganography method with hierarchical security was proposed. First, multiple types of data in the whole cover document were regarded as optional steganographic covers to build up a hierarchical security steganographic model upon the the steganographic security levels defined by taking the characteristics of different types of data and the steganalysis as evaluation criterions. Then, a security level was adaptively determined by the secret message length, and the secret message was embedded into the selected independent different types of data in a cover document with the help of the built model. Theoretical analysis and experimental results show that compared with the steganography based on single data, the proposed method has expanded the steganographic capacity and reduced the modifications of the statistic characteristics of a single type of data in the cover document when the same secret message was embedded. In conclusion the proposed method improves the security of the secret message.