隐写术中的编码模型及方法研究

Coding Model and Methods for Steganography

隐写术的目的是将秘密消息嵌入到多媒体数据中进行隐蔽传输。为了提高安全性,嵌入过程希望对载体做尽量少的修改并避免对敏感区的修改。这个数据嵌入问题可以用隐写码来解决。文章按照发送方拥有的边信息情况,将隐写编码问题分为三种模型:基本模型,湿纸模型和湿度级模型。对各种模型的下编码方法作了介绍,并以灰度图像上的±1隐写为例说明了隐写码可以大幅度提高隐写术的安全性。

The purpose of steganography is covert communication by embedding secret messages into multimedia data.To improve security,the steganographer hope to modify less cover elements and avoid changing sensitive fields of the cover.This problem can be solved by steganographic codes（stego codes）.According to side information using by the sender,we divide stego codes into three models：basic model,wet paper model and wet-scale model.We review coding methods in each coding model,and show that stego codes can greatly improve security of steganograpy by taking ±1embedding in grayscale images as an example.