Steganography

What is Steganography

Steganography is defined by Merriam-Webster as the art or practice of concealing a message, image, or file.

Different Types of Steganography

There are many different types of Steganography. However, they all share the same goal of hiding the presence of some particular piece of data.

Micro Dots

Micro dots are used to shrink the physical size of a document or image. This technique was used heavily during World War I and World War II. A person wanting to send data secretly to another person would need to use something called a Micro Dot Camera to take a picture of thing they want to send. Once they have the picture the Micro Dot would then either be applied to a document and mailed or just attached to a carrier pigeon. Of course you would want to make sure the document has some information on it that someone could easily read, otherwise they might suspect you are trying to hide something from them. Sizes of the various types of Micro Dots differ due to the wide variety of applications. Currently, they are being sprayed onto laptops and car parts to try and stop reselling of the equipment.

Null Ciphers

Null Ciphers are even probably one of the simpler forms of steganography. All it requires is a pre-shared key that both the sender and receiver know. Here is an example of a null cipher:

PRESIDENT'S EMBARGO RULING SHOULD HAVE IMMEDIATE NOTICE. GRAVE SITUATION AFFECTING INTERNATIONAL LAW. STATEMENT FORESHADOWS RUIN OF MANY NEUTRALS. YELLOW JOURNALS UNIFYING NATIONAL EXCITEMENT IMMENSELY.

Take the first letter of each letter of each word and you get PERSHINGSAILSFROMNYJUNEI which is PERSHING SAILS FROM NY JUNE I after you apply spaces.

Hiding Data in an Image

Hiding data in images is probably the most prevalent form of Steganography used today. It is rumored that terrorist organizations use this technique to spread information to its members.