Steganography- Hiding Information in Text..!!!

Now let us discuss various methods for hiding information using different covers:

Hiding Methods in WW2 (World War 2) :

In WW2 the hardly visible dots (microdot technology) still were used to denote the selected letters in a Newspaper. For example, many soldiers tried to send home hidden messages that way, but the method was well known by the censors. (If they cannot discover the hiding method, they mixed the words at least or put the stamp in another position, etc.)

Null ciphers (unencrypted messages) :

“Apparently neutral's protest is thoroughly discounted and ignored. Isman hard hit. Blockade issue affects pretext for embargo on by products, ejecting suets and vegetable oils.”

Sent by a German Spy in WWII, by taking the second letter in each word the following message emerges: Pershing sails from NY June 1.

Denoting some way the letters of the carrier text to hide a secret message in it. For example,

•    Microdot Technology : Shrinking messages down to the size of a dot became a popular method. Since the microdot could be placed at the end of a sentence or above a ‘j’ or an ‘i’.
•  Hardly visible dislocation of the selected letters.
•  Very little modification of the shapes of selected fonts.

Advantages :

•  Methods when the hidden information is carried by the appearance of the text, (not only the text file.)
• Such a way the printed or copied text also carries the hidden information. (E.g. a confidential circular letter.)

Disadvantages :

•  This makes difficult to select out the appropriate letters by a computer.
• The printing/copying/scanning processes bring additional problems to revoke the hidden text.

Marking the selected letters in the covering text by another ways : 

Each font in the text occupies a standard area. That area is not necessarily the same for each font. For example, the letter ‘m’ is generally wider than the letter ‘i’. (Proportional vs. fix font size.) Any letter could be moved or modified a bit within its standard font area. Such way particular letters of a carrier text could be marked. The marked letters can be selected out of the text by an appropriate program. (The text could be photocopied as well.)

Moving the selected fonts : 

Text processors, like Word, WordPerfect and Desktop publishing softwares, like Adobe’s PageMaker, FrameMaker, of ‘wysiwyg’ (what you see is what you get) generally cannot move the selected fonts. “Programmable” text processors (like LateX) are able to move the selected fonts. Such application needs a separate selecting program which is able to accept picture files as well. (E.g. scanned or copied texts). This is not a simple job and the addressee must have it in advance. The character recognizer software looses such hidden information.

Modifying fonts : 

This can be done by increasing the length of vertical lines in some of the characters like (b,d,h,k,l,p,q)  with the small amount is not prominent. This also may carry information. Arabic writing allows many decorative variations of the letters in a text, which may be used to mark selected letters.

Method for hiding the coded information into text : 


In this method, at the ends of rows we may insert extra spaces. Each space at a row-end may represent a single bit. (Max 3 spaces, for more than 3 could be conspicuous.) In an A4 page there are 50 rows and altogether 50x3 bit= 150 bits (less than 20 bytes) could be hidden such a way. This method can resist compression.

• One has to read the first letters of words preceded by double spaces.
• Modifying the font sizes or spaces.

Modifying the structure of text : 

In this method, synonyms of some words can be used instead of the original word, or changing the linguistic structure of the text (applicable in most cases). This method can be used to hide information. Revocation the hidden information the original text (like a key) is needed. Very small amount of information can be hidden that way.