Steganography

STEGANOGRAPHY

BY:SAUGATA PALIT

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

The word steganography is of Greek origin and means "concealed writing" from the Greek words  “steganos” meaning "covered or protected", and ”graphei”  meaning "writing".

Generally, messages will appear to be something else: images, articles, shopping lists, or some other covertext.

INTRODUCTION

Media files are ideal for steganographic transmission because of their large size.

As a simple example, a sender might start with an image file and adjust the color of every “100th” pixel to correspond to a letter in the alphabet, a change so subtle that someone not specifically looking for it is unlikely to notice it.

Image extracted Steganographically hidden

image

The advantage of steganography over cryptography alone is that messages do not attract attention to themselves. Plainly visible encrypted messages—no matter how unbreakable—will arouse suspicion, and may in themselves be incriminating in countries where encryption is illegal.Therefore, whereas cryptography protects the contents of a message, steganography can be said to protect both messages and communicating parties.

STEGANOGRAPHY vs CRYPTOGRAPHY

A steganography software tool allows a user to embed hidden data inside a carrier file, such as an image or video, and later extract that data.

Some common steganography tools are :a) SNOWb) S-TOOLSc) STEALTHd) HIDE and SEEKe) PARANOID

STEGANOGRAPHY TOOLS

• Snow steganography also known as “Whitespace steganography” is used to conceal messages in ASCII text by appending the white spaces to the end of the line.

•  As spaces and tabs are generally not visible in text viewers, the message is effectively hidden from casual observers.

• Snow exploits the steganographic nature of whitespace.Locating /trailing whitespace in text is like finding a polar bear in a snowstorm.

SNOW

The snow program runs in two modes - message concealment, and message extraction.

During concealment, the following steps are taken:

Message -> optional compression -> optional encryption -> concealment in text

Extraction reverses the process:

Extract data from text -> optional decryption -> optional uncompression -> message

Working of SNOW

S-Tools is a program that helps you hide your files and folders using steganography - it hides your data within graphics files (BMP, GIF) and WAV files (music) in such a way that the files are no different from those not containing any hidden data (that is, the picture can still be viewed, the music can be listened to).

Digital files (like *.bmp or *.wav) can be to some extent modified so that the changes will not affect the quality of image or sound (i.e. the changes will be virtually unnoticeable).

The program not only hides your data within a seemingly usual file but it enables you to encrypt the hidden data as well.

S-TOOLS

S-Tools is somewhat less powerful in that it lacks features such as the ability to hide data within HTML and text files, and irrecoverable data deletion.

Working of S-TOOL You open up a copy of

S-Tools and drag pictures and sounds across to it. To hide files you just drag them over open sound/picture windows. You can hide multiple files in one sound/picture and your data is compressed before being encrypted then hidden.

Camouflage allows you to hide files by scrambling them and then attaching them to the file of your choice. This camouflaged file then looks and behaves like a normal file, and can be stored, used or emailed without attracting attention.

Example, you could create a picture file that looks and behaves exactly like any other picture file but contains hidden encrypted files, or you could hide a file inside a Word document that would not attract attention if discovered. Such files can later be safely extracted.

CAMOUFLAGE

For additional security you can password your camouflaged file. This password will be required when extracting the files within. You can even camouflage files within camouflaged files.les can later be safely extracted.

Steganalysis is the art and science of detecting messages hidden using steganography.

The goal of steganalysis is to identify suspected packages, determine whether or not they have a payload encoded into them, and, if possible, recover that payload.

Steganalysis generally starts with a pile of suspect data files, but little information about which of the files, if any, contain a payload.

STEGANALYSIS

THANK

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