Steganography

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BY

N.HIMASINDHU

P.SHANKAR

K.VAMSHI

J.RAM BABU

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The term Steganography comes from the Greek words for covered writing.

Steganography is the art of covered or hidden writing.

The purpose of steganography is covert communication-to hide the existence of a message from a third party.

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Thousands of years ago, the Greeks used staganography to hide information from their enemies.

One hiding method was to engrave a message in a block of wood, then cover it with wax, so it looks like a blank wax tablet. when they wanted to retrieve the message, they would simply melt off the wax.

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We can also perform steganography using a computer.

Everything in a computer is stored as 1’s and 0’s (a bit).Bits are grouped in sets of eight, one set is called a byte.

01000001 = A01000010 = B01000011 = C

001

Bits

One byte can be used to represent each letter of the alphabet. This is what is used in text files.

1001100011111111

Bytes

00001000

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11111000 11001001 00000011

Pictures are made up of lots of little dots called pixels. Each pixel is represented as 3 bytes – one for red, one for green and one for blue.

Each byte is interpreted as a number, which is how much of that colour is used to make the final colour of the pixel.

248 201 3

248 + 201 + 3 = Orange Colour

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The difference between two colours that differ by one in either one red, green or blue value is impossible to see with the human eye.

248 + 201 + 3 = Original Colour

247 + 201 + 3 = Red -1

248 + 201 + 4 = Blue +1

If we change the least significant (last) bit in a byte, we either add or subtract one from the value it represents.

This means we can overwrite the last bit in a byte without affecting the colour it appears to be.

We can use images to hide things if we replace the last bit of every colour’s byte with a bit from the message.

01000001Message: A

Image with 3 pixels:

11111000 11001001 00000011 11111000 11001001 00000011 11111000 11001001 00000011

Pixel 1:

Pixel 2:

Pixel 3:

Now we hide our message in the image:

Pixel 1:

Pixel 2:

Pixel 3:

11111000 11001001 0000001011111000 11001000 0000001011111000 11001001 00000011

New image:

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Even if we do this across a big image and with a really large message, it is still hard to tell that anything is wrong.

Original With Hidden Message

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EXISTING SYSTEMThis application is platform dependent.

Supports any one either command mode or graphical mode.

Should be applicable for any kind of image size for steganography.

PROPOSED SYSTEMThis application is platform independent.

Supports both command mode and graphical mode

Provide interactive interface through which user can interact with different types of Images, Image Sizes and Text Messages.

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HARDWARE REQUIREMENTSProcessor:: Pentium-III (or) Higher

Ram:: 64MB (or) Higher

Cache:: 512MB

Hard disk:: 10GB

SOFTWARE REQUIREMENTSTools:: Micro Soft Front

Operating System:: WindowsNT/2000

Client Side:: GUI

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In this we have 2 modules Steg module : In this module User need to write any secret information in Text area provided and need to select an Image file to which User wants to append the Secret Information Text .

In UnSteg module the Encrypted Image will be selected and Steganography Application will start decrypting it with each and every pixel of the Image and displays the output i.e. Secret Text Information

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This is output screen

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This is a steg module in which secret text is typed as shown above

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Selecting image and appending the secret information in to image which is also steg module

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The secret information is added in this image

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This is unsteg module ,i.e. the encrypted image file is selected.

The encrypted image file is saved in the same folder of the image which we are selected to encrypt

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Here decrypting image is done ,which is also an unsteg module

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This is decrypted secret information from encrypted image

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Technical feasibility

Operational feasibility

Economical feasibility: Cost benefit analysis Long-term returns Maintenance costs

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steg

messageimage

selectmessage()selectimage()

encryption

textimageencryption

takeimage()taketext()encrypt()createnewimage()

unsteg

decryption

takedecryptedimage()

decryption

decryptdisplayimage

decrypt()displayimage()

Class diagram of steganography

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Encryptionsteg module unsteg decryptionuser

2.Take Message & image

3.create a new image file with encrypted message

6.take encrypted image

7.display secret text

1.select message and image

4.send new image file

5.select encrypted image file

8.display decrypted message

Sequence diagram for steganography

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select secret text

select image file

select steg module

select unsteg module

user

Usecase diagram for steganography

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Allows user to hide large amounts of information within image and audio files.

These forms of steganography often are used in conjunction with cryptography so that the information is doubly protected

Stego may, in fact, be all too real —

There have been several reports that the terrorist organization behind the September 11 attacks in New York City, Washington, D.C., and outside of Pittsburgh used steganography as one of their means of communication.

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