Monday, October 23, 2006

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

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