digital camera or a scanner, the dual statistics steganalysis indicates that the safe bit-
rate is less than 0.005 bits per sample, providing a surprisingly stringent upper bound
on steganographic capacity of simple LSB embedding.
Pfitzmann and Westfeld
[12] introduced a method based on statistical analysis of
Pairs of Values (PoVs) that are exchanged during message embedding. For example,
grayscales that differ in the LSBs only, could form these PoVs. This method, which
became known as the χ
2
attack, is quite general and can be applied to many
embedding paradigms besides the LSB embedding. It provides very reliable results
when the message placement is known (e.g., for sequential embedding). Pfitzmann
[12] and Provos [13] noted that the method could still be applied to randomly
scattered messages by applying the same idea to smaller portions of the image while
comparing the statistics with the one obtained from unrelated pairs of values.
Unfortunately, no further details regarding this generalized χ
2
attack are provided in
their papers, although Pfitzmann [12] reports that messages as small as one third of
the total image capacity are detectable.
Farid [14] developed a universal blind detection scheme that can be applied to any
steganographic scheme after proper training on databases of original and cover-
images. He uses an optimal linear predictor for wavelet coefficients and calculates the
first four moments of the distribution of the prediction error. Fisher linear
discriminant statistical clustering is then used to find a threshold that separates stego-
images from cover-images. Farid demonstrates the performance on J-Steg, both
versions of OutGuess, EZ Stego, and LSB embedding. It appears that the selected
statistics is rich enough to cover a very wide range of steganographic methods.
However, the results are reported for a very limited image database of large, high-
quality images, and it is not clear how the results will scale to more diverse databases.
Also, the authors of this paper believe that methods that are targeted to a specific
embedding paradigm will always have significantly better performance than blind
methods.
Johnson and Jajodia
[15] pointed out that some steganographic methods for palette
images that preprocess the palette before embedding are very vulnerable. For
example, S-Tools [10] or Stash [10] create clusters of close palette colors that can be
swapped for each other to embed message bits. These programs decrease the color
depth and then expand it to 256 by making small perturbations to the colors. This
preprocessing, however, will create suspicious and easily detectable pairs (clusters) of
close colors.
Recently, the JPEG format attracted the attention of researchers as the main
steganographic format due to the following reasons: It is the most common format for
storing images, JPEG images are very abundant on the Internet bulletin boards and
public Internet sites, and they are almost solely used for storing natural images.
Modern steganographic methods can also provide reasonable capacity without
necessarily sacrificing security. Pfitzmann and Westfeld [16] proposed the F5
algorithm as an example of a secure but high capacity JPEG steganography. The
authors presented the F5 algorithm as a challenge to the scientific community at the
Fourth Information Hiding Workshop in Pittsburgh in 2001. This challenge stimulated
the research presented in this paper.
In the next section, we give a description of the F5 algorithm as introduced in [16].
Then, in Sect. 3, we describe an attack on F5 and give a sample of experimental
剩余15页未读，继续阅读
Wzy_CC
- 粉丝: 0
- 资源: 3
我的内容管理
展开
最新资源
- zlib-1.2.12压缩包解析与技术要点
- 微信小程序滑动选项卡源码模版发布
- Unity虚拟人物唇同步插件Oculus Lipsync介绍
- Nginx 1.18.0版本WinSW自动安装与管理指南
- Java Swing和JDBC实现的ATM系统源码解析
- 掌握Spark Streaming与Maven集成的分布式大数据处理
- 深入学习推荐系统：教程、案例与项目实践
- Web开发者必备的取色工具软件介绍
- C语言实现李春葆数据结构实验程序
- 超市管理系统开发：asp+SQL Server 2005实战
- Redis伪集群搭建教程与实践
- 掌握网络活动细节：Wireshark v3.6.3网络嗅探工具详解
- 全面掌握美赛：建模、分析与编程实现教程
- Java图书馆系统完整项目源码及SQL文件解析
- PCtoLCD2002软件：高效图片和字符取模转换
- Java开发的体育赛事在线购票系统源码分析
资源上传下载、课程学习等过程中有任何疑问或建议，欢迎提出宝贵意见哦~我们会及时处理！
点击此处反馈
