Sandeep KumarMCA (6th sem)

Table of Contents :

• Introduction• History• Past use• Modern use• Advantages• Disadvantage• Steganography vs. cryptography• Conclusion• Reference

Introduction :

• It is an art of hiding information into any digital images.

• Only sender and receiver, suspects the existence of the message.

Introduction (contd.):

• It is mixture of two Greek words : Steganos :- Covered or Protected Graphei :- Writing

That’s why called Hiding of image or information or covered writing

• In this we Combine secret image / file with current image which gives the hidden image.

• The hidden image is difficult to detect without retrieval.

Can be hidden in digital data

• MS Word (doc)• Web pages (html)• Executables (exe)• Sound files (mp3, wav,)• Video files (mpeg, avi)• Digital images (bmp, gif, jpg)

History Of Steganography :

• Steganographic techniques have been used from ancient ages.

• The aim of steganographic communication back and now, in modern applications, is the same i.e. to hide secret data.

Past use :• Hidden messages within wax tablets — in

ancient Greece, people wrote messages on the wood, then covered it with wax .

Past use (contd.) :• Hidden messages on messenger's body

also used in ancient Greece.• In this the message tattooed on the

shaved head.• Hidden by the hair that afterwards

grew over it, and exposed by shaving the head again.

• This method has obvious drawbacks, such as delayed transmission while waiting for hair to grow and limited size also.

Past use (contd.) :• During World War II, the French sent some messages

written on the backs of couriers using invisible ink.• Hidden messages on paper written by secret inks,

under other messages or on the blank parts of other messages. Which was latterly retrieve by either rays or fire , etc.

Past use (contd.) :• Jeremiah Denton repeatedly blinked his eyes in

Morse Code .• During 1966 televised press conference that he was

forced into as an American POW by his North Vietnamese captors, spelling out the word, "T-O-R-T-U-R-E“.

Modern Use :

• Modern steganography entered the world in 1985 when personal computer being applied to classical steganography problems.

• Here we hide our secret data / messages into :– Digital Images.– Audio.– Video , etc.

Here steganography is done with the help of Steganography tool.

Steganography In Images :

• Messages are hidden in background.• May be anywhere in image.• Cannot see message in image without encryption.• This is done with the help of least significant bit (LSB).

Original Image :

Encrypted Image : Hidden Image :

This is how modern Steganography Works.

Still Problem !!!Here we go through live example with Steganography tool.

Advantages :

• Top Secret – No body apart from sender and receiver can retrieve message.

• Hide messages like – Images , Audio , Video , text , etc.

• Used by Intelligence Bureau – To send their Secret messages.

Disadvantages :

Apart from advantages there are also disadvantage too.

• Used by terrorists : In 9/11 attack al-Qaeda head Bin Laden used this technology.

• In an image he encoded whole message and then transport it via e-mail.

Lets see how he done this :

Not exact image .Just for example.

Is it just an image ?????

No !!!!!This is much more than an image.It holds messages in it.

Steganography vs. Cryptography

Steganography Cryptography

Hide the message Does not hide message

Only sender and receiver knows the existence of message

Everybody knows the existence of message

End result is stego-media End result is cipher-text

Used from ancient time till modern era Used in modern era

Conclusion

• Hiding information.• Secret among sender and receiver.• Having both aspects i.e. good and bad use.

Reference

• http://en.wikipedia.org/wiki/Steganography• http://www.webopedia.com/TERM/S/stegano

graphy.html - For definition.

• http://www.slideshare.net/ • Steganography- A Data Hiding Technique .pdf

file by - Arvind Kumar and Km. Poona Assistant Professor Meerut (INDIA).