What are the techniques of Text Steganography in Information Security?

Steganography is the art and science of concealing a message within another message without drawing some suspicion to others so that the message can only be identified by its intended recipient.

There are various techniques of text steganography which are as follows −

Line-shift coding − Features are marked into the text by changing the lines, so as to create recognition harder. Text lines are vertically changed for encoding. This can be used to either a format file or to the bitmap of a page.

By transforming each second line of the document 1/300th of an inch up or down, line-shift encrypting provide that files can be encrypted and decrypted properly. A set of drawbacks include the fact that it is complex to remove encoding and also that it is the clearest form of coding.

Word-shift coding − Word spacing is completed in a fixed pattern, therefore that even the fact that a message is present is unfamiliar. Words are coded into a file by changing the horizontal locations of words inside text lines, while supporting a natural spacing appearance.

For instance, the largest and smallest spaces between words are discovered. It can code a line, the largest spacing is decreased by a specific amount and the smallest is increased by the similar amount.

Therefore, line length is supported and change is not visible. But this method is not reliable either, as if the spaces between words are calculated, the encoded information can be revealed.

Feature coding − Characteristics of the letters themselves are modified. The specific ways in which specific letters are written forms a code by itself. For instance, the end-lines of d, h, b etc. can be changed.

This is hugely indiscernible and can be directly utilized on the image file. The only method in which this code can be attacked is by compensating each end-line to a constant value. However, this is tedious and painstaking and is generally not completed.

There are some other interesting alternative methods are accessible, but are still in their infant stages. These include are as follows −

  • It can be using grammar to encode data.

  • It can be used to Syntactic encoding.

  • It can be used to Semantic encoding.

Software to hide information in text (textual steganography) appears in several versions such as Texthide, Webstego and Steganos. All these enable the communication of encrypted responsive information through plain text files in a format not recognizable by a third party.

Syntactic Method − This technique need punctuation marks including full stop (.), comma (,), etc. to hide bits 0 and 1. But problem with this approach is that it needed identification of correct places to add punctuation marks. Thus, care should be taken in utilizing this method as readers can notice inadequate use of the punctuations.