Hacking For Beginners – Manthan Desai
2010
5. What Is Steganography?
Steganography is the art and science of hiding messages. Steganography combined with cryptography so thateven if the message is discovered it cannot be read.
The word steganography is derived from the Greek words "steganos" "graphein", which mean "covered" and"writing." Steganography, therefore, is covered writing.
Historical stenganography involved techniques such as disappearing microdots. Modern steganography involveshiding data in computer files.
It is fairly easy to hide a secret message in a graphic file without obviously altering the visible appearance of that file.
Steganography software
OutGuess is a universal steganographic allows the insertion of hidden information into the redundant bits ofdata sources. The nature of the data source is irrelevant to the core of OutGuess. The program relies on data specifichandlers that will extract redundant bits and write them back after modification. In this version the PNM and JPEG imageformats are supported. In the next paragraphs, images will be used as concrete example of data objects, though OutGuesscan use any kind of data, as long as a handler is provided.
F5 is a publicly available steganography software package which hides messages in BMP, GIF , and JPG graphics.
Camera/Shy is the only steganographic tool that automatically scans for and delivers decrypted content straight from theWeb. It is a stand-alone, Internet Explorer-based browser that leaves no trace on the user's system and has enhancedsecurity.
JPHIDE and JPSEEK are programs which allow you to hide a file in a jpeg visual image. There are lots of versions of similarprograms available on the internet but JPHIDE and JPSEEK are rather special. The design objective was not simply to hidea 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 atypical visual image, a low insertion rate (under 5%) and the absence of the original file, it is not possible to conclude withany worthwhile certainty that the host file contains inserted data. As the insertion percentage increases the statisticalnature of the jpeg coefficients differs from "normal" to the extent that it raises suspicion. Above 15% the effects begin tobecome visible to the naked eye. Of course some images are much better than others when used a host file - plenty offine detail is good. A cloudless blue sky over a snow covered ski paradise is bad. A waterfall in a forest is probably ideal.
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