Microsoft Excel File: A Steganographic Carrier File

2. Literature Review

Encoding secret message in text can be a challenging task. This is because text files have small amount of redundant data that is to be replaced with a secret message. Another drawback is the easy alteration of characters which can be done by unwanted parties. There are some methods by which we can accomplish text based steganography. These methods are:

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  Open Space Method

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  Syntactic Method

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  Semantic Method

There are numerous ways to employ the open space in text files to encode the information. This method works because a casual reader may avoid one extra space at the end of line and an extra space between two words does not prompt abnormality. The extra space can be used to conceal one bit either 0 or 1. However, inter sentence space method encodes a “0” by adding a single space after a period in English prose. Adding two spaces would encode a “1”. The left shift encoding involves actually shifting each line of text vertically up or down by as little as three centimeters. The End-of-line space method exploits white space at the end of each line.