Package: File Camouflage

Want to save a copy of your personal file on a usb pendrive but you are worried that, in case of theft, someone will be able to access your data?

With Free File Camouflage you can hide your files inside a jpeg image!

The software can be used with the main interface or via the explorer "send to" context menu (the first time you only need to select a directory with some images).

All the files are encrypted using AES and hidden inside an image.

What happens if someone tries to open a camouflaged image? Well... nothing! He will only see the image.

Download

中文網頁介紹

Paper: Detecting Low Embedding Rates

Author: Andreas Westfeld

Information Hiding Workshop 2002 (IHW 2002)
Noordwijkerhout, The Netherlands, 7–9 October 2002

Springer-Verlag Berlin Heidelberg,
LNCS 2578, pp. 324–339, 2003.


Abstract

This paper shows three approaches for detecting steganograms with low change density. MP3Stego is a steganographic algorithm with a very low embedding rate. The attack presented here is a statistical analysis of block sizes. It is able to detect 0.001 % of steganographic payload in MP3 files. The second approach is the use of hash functions to combine sample categories for the chi-square attack. One of these hash functions enables us to detect about 0.2 bits per pixel in true colour images. Another algorithm (Hide) was presented at the last workshop and constructed to be secure against visual and statistical chi-square attacks. The detection method for Hide combines the three colour components of each pixel to recognise an increased number of "neighbour colours".

From StegoRN

這篇論文提出三個偵測低嵌入量(改變量)的隱藏分析技術:

1. 針對 MP3Stego -
分析 MP3 檔案中, 每一個 block 的大小, 透過統計的方式找到一般 MP3 檔案不會出現的特徵, 藉此判定是否被 MP3Stego 這個隱藏工具嵌入機密訊息。實驗結果顯示, 當嵌入量為 MP3 檔案所能提供嵌入量的 0.001% 時, 此論文所提出的方法就可以辨識出來。

2. 提升卡方攻擊法(Chi-Square Attack)的偵測能力
第二個技術是透過雜湊函數(hash function) 整合樣本分群(sample category), 然後再使用原來的卡方攻擊法分析。本論文提到透過某種雜湊函數確實可以使卡方攻擊法偵測出儘含有 0.2 bpp 的彩色影像(true color image)。

3. 針對 Hide
Hide 是 IHW 2001 所提出來的隱藏軟體, 其使用的 LSB Matching 的技術可以抵抗卡方攻擊法的分析。這篇論文透過觀察每個色彩的臨色總數(the number of neighbor colors), 發現嵌有機密訊息的影像, 臨色總數明顯增加許多。

From StegoRN

From StegoRN

From StegoRN

S-Tools

Author: Andy Brown
Ver. 1.0 (1994), Ver. 2.0 (1994), Ver. 3.0 (1995), Ver. 4.0 (1996)

最早接觸到 S-Tools 這個隱藏軟體是從 Neil F. Johnson 1998 February 發表在 IEEE Computer 的文章 "Steganography: Seeing the Unseen", 文章中所使用的例子是將 CORONA 偵查衛星於1966/08/20 所拍攝的前蘇聯哈薩克戰略轟炸機基地空照圖 (Soviet strategic bomber base) 隱藏到印象派大師 Pierre-Auguste Renoir (1841-1919) 的畫作 Le Moulin de la Galette (1876) 之中, 讓我印象深刻。

JPHIDE and JPSEEK Offical Website

1999年 8 月推出的 JPHIDE and JPSEEK,
作者: Allan Latham ( alatham@flexsys-group.com ),
官方網站網址: http://linux01.gwdg.de/~alatham/stego.html。
在官網中, 作者對於這個隱藏軟體的描述如下:

JPHIDE and JPSEEK are programs which allow you to hide a file in a jpeg visual image. There are lots of versions of similar programs available on the internet but JPHIDE and JPSEEK are rather special. The design objective was not simply to hide a file but rather to do this in such a way that it is impossible to prove that the host file contains a hidden file. Given a typical visual image, a low insertion rate (under 5%) and the absence of the original file, it is not possible to conclude with any worthwhile certainty that the host file contains inserted data. As the insertion percentage increases the statistical nature of the jpeg coefficients differs from "normal" to the extent that it raises suspicion. Above 15% the effects begin to become visible to the naked eye. Of course some images are much better than others when used a host file - plenty of fine detail is good. A cloudless blue sky over a snow covered ski paradise is bad. A waterfall in a forest is probably ideal.

其大意是這樣的:

JPHIDE and JPSEEK 是一個可以將檔案藏進 JPEG 影像的程式。在 Internet 上, 有許多類似程式及其各種版本, 然而, JPHIDE and JPSEEK 卻相當特別！JPHIDE and JPSEEK 的設計目的並不僅是簡單地隱藏檔案, 反而是進一步要表達: 要證明某張偽裝影像嵌有檔案是不可能的。給定一個嵌有低嵌入比例 (低於 5% ) 的影像, 在沒有原始影像的情況下, 並沒有辦法去判斷這張影像嵌有訊息的。當嵌入比例增加時, JPEG 係數的統計特性偏離了原來的正常範圍, 就會引起懷疑。超過 15% 的嵌入比例時, 對於影像品質的影響是肉眼可見的。當然, 擁有較多細節的影像是比較適合用來做掩護影像 ( host ) 的。例如: 一張藍天無雲的滑雪天堂的圖片, 就不太適合用來嵌入訊息; 在森林中瀑布拍攝的圖片就是一張理想的掩護影像。

JPHIDE and JPSEEK 有兩個版本:
1. JPHS 0.3 是 Linux 版本, Download: JPHS 0.3 & Signature
2. JPHS 0.5 則是 Window 版本, Download: JPHS 0.5

JPHS 0.5 的執行畫面如下:

From StegoRN