Steganography

Steganography

What is Steganography?What is Steganography?

Greek Words:

STEGANOS – “Covered”

GRAPHIE – “Writing”

Steganography is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message.

This can be achieve by concealing the existence of information within seemingly harmless carriers or cover

Branches of Information Hiding

There are two major branches of information hiding, Steganography and Watermarking

Watermarking: Communication in watermarking is the host signal, with

the embedded data providing copyright protection. The existence of a watermark is often declared openly. Any attempt to remove or invalidate the embedded

content renders the host useless. They are of two types: Visible watermarking Invisible watermarking

Once the presence of hidden information is revealed or even suspected, the purpose of steganography is defeated.

History of Steganography History of Steganography

Demeratus sent a warning about a forthcoming attack to Greece by writing it on a wooden panel and covering it in wax.

Histiaeus, who shaved the head of his most trusted slave and tattooed a message on it. After his hair had grown the message was hidden. The purpose was to instigate a revolt against the Persians.

World War II

Invincible inks 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.

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.

Modern Steganography Techniques

Masking and Filtering: Is where information is hidden inside of a image using digital watermarks that include information such as copyright, ownership, or licenses.

Algorithms and Transformations: This technique hides data in mathematical functions that are often used in compression algorithms. The idea of this method is to hide the secret message in the data bits in the least significant coefficients.

Least Significant Bit Insertion: The most common and popular method of modern day steganography is to make use of the LSB of a picture’s pixel information.This technique works best when the image file is larger then the message file and if the image is grayscale.

Basics of Modern SteganographySteganography

fE:     steganographic function "embedding"fE-1:   steganographic function "extracting"cover:  cover data in which emb will be hiddenemb:    message to be hiddenkey:    parameter of fEstego:  cover data with the hidden message

Important Requirement for Important Requirement for Steganographic SystemSteganographic System

Security of the hidden communication

Robustness against statistical attacks

Robustness against image manipulations

Applications

Usage in modern printers

Alleged use by terrorists

Alleged use by intelligence services

Alleged use by terrorists

Origional Encrypted Image

Detection of Steganographic Detection of Steganographic Content/CountermeasuresContent/Countermeasures

The detection of steganographically encoded packages is called Steganalysis.

Visual Analysis tries to reveal the presence of secret communication through inspection, either with the naked eye or with the assistance of a computer.

Statistical (Algorithmic) Analysis reveals tiny alterations in an image's statistical behavior caused by steganographic embedding.

The nominally universal methods developed to detect embedded stego-data are generally less effective than the steganalytic methods aimed at specific types of embedding.

Steganography Sample Steganography Sample WebsiteWebsite

Here is the link for Sample Steganographic tool Website:

http://mozaiq.org/

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