分层的文本信息隐藏研究

针对文本载体冗余度小的问题,提出一种在文本中分层隐藏信息的技术,建立了一个由待藏信息表示层、待藏信息加密层、载体内容层、载体内码层和载体版式层五个层次组成的隐藏模型.待藏信息表示层将待藏信息编码成不可读的符号序列,待藏信息加密层则对这些不可读符号序列进一步加密.载体内容层在句法、语义和语用上对前一层的输出进行嵌入隐藏,载体内码层和载体版式层分别通过选择载体文字自身的机器编码标准及版式来隐藏信息.每层有控制信息和数据信息作为参数,各层各司其职,高度独立.根据不同的隐藏要求,可以选择跳过某层,直接进入下层.介绍了各层的隐藏技术和方法,并在微软的Word文本中实现了该5层隐藏模型.

Study of Layered Information Hiding in Text Document

A 5-layer model and techniques are proposed to hide information in text documents which are less redundant than images, video, and audio. The model consists of presentation layer, encrypt layer, carrier-content layer, carrier-code layer and carrier-format layer. At the presentation layer, the message to hide is encoded to unreadable symbol sequence, then encrypted at the encrypt layer. At the carrier-content layer, the output of encrypt layer is embedded in the carrier syntactical, semantic and pragmatic planes respectively. Then the output of encrypt layer can be embedded in multiple carrier coding at carrier-code layer and in diverse carrier formats at carrier-format layer. The layers are independent, each of them employs own control message and data as parameters, and executes different operation. All layers are optional, one or more can be skipped. The hiding techniques and approach at each layer are introduced, and a prototype system is implemented for the Microsoft Word document.