Steganography in digital image processing is viewed as a future technology, in processing image and hidden techniques behind sending an image secretly by covering it up something.

1. Steganography
By
Shri Swetha. M
Shri Sailaxmi. S

2. Overview
• Steganography
• Aim of Steganography
• History of Steganography
• Cryptography Vs Steganography
• Types of Steganography
1. Text Steganography
2. Image Steganography
3. Audio Steganography
• Advantages of Steganography
• Disadvantages of Steganography
• Applications of Steganography

3. INTRODUCTION
• Steganography is an art of hiding
data within data.
• Stego means covering and grafia
means writing.
• Steganography is one of the
oldest forms of cryptology

4. History of Steganography
• Invisible ink has been a popular form by the ancient Greeks and
Romans over 2000 years ago, even during II world war.
• The first invisible inks used organic substances, such as, diluted
lemon juice, vinegar, milk, sweat, saliva, onion juice or many other
organic substances. The recipient would reveal the message by
applying a flame to the paper.
• A mixture of alum and vinegar was used to write on a hard-boiled
egg. The message could only be read after peeling the egg to see the
message on the albumen.
• Wax tablets were in common use then as reusable writing surfaces,
sometimes used for shorthand.

5. Aim of Steganography
1) Confidential communication and
secret data storing
2) Protection of data alteration
3) Access control system for digital
content distribution
4) Media Database systems

6. Method of providing security to
information
• We have two methods to provide security to information.

7. Cryptography
• Cryptography is the study of hiding information and it
is used when communicating over an untrusted
medium such as internet, where information needs
to be protected from other third parties.

8. Steganography
• 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, a form of security through
obscurity.
• "Steganography means hiding one piece of data within another".
• E.g.

9. Cryptography Vs Steganography

10. EMBEDDING METHODS
TYPES
Spatial Domain
Embedding
LSB
Frequency
Domain
Embedding
DCT
DWT

11. TYPES OF COMPRESSION
• To improve the process message
compression can be applied.
• It was found that lossless
compression produces better
result.
• In this the originality of digital
image is maintained.
COMPRESSION
LOSSY LOSSLESS

12. TYPES OF STEGANOGRAPHY
•Text/Documents
•Images
•Video
•Audio

13. Steganography In Text/Documents
• STEPS FOLLWED IN A IMAGE FILE STEGANOGRAPHY
1. Data can be either in colour image or grey scale image.
2. Image is embedded using cryptography algorithm.
3. The embedded data is embedded into the image file which turns into
a stego image.
4. Stego key is used during the hiding process to send the image
securely.
5. After the image is received, the receiver will extract the data from
image.
6. In order to extract the message the receiver requires a shared key.
THIS APPROACH IS CALLED STEGO KEY APPROACH

14. Steganography In Images
• Images are composed of dots called
PIXELS.
• 8-bit and 24-bit per pixel image files.
• Each pixel gets its own color by
combining percentages of red, green
and blue(RGB).
• For 8bit each of these colors has value
from 0 to 225.
• E.g.10GB of pictures are transmitted
over a connection. Then at most 3GB
of steganographically hidden data can
be transmitted using them as carriers.

15. Image/Video watermarking
• Spatial domain watermarking
- bit flipping
- color separation
• Frequency domain watermarking
- embed signal in select frequency bands (e.g. high frequency areas)
- apply FFT/DCT transform first
- e.g. Digi marc
- watermark should alter the least perceptible bits
-these are the same bits targeted by lossy image compression software.
- used by most networks (logo at bottom-right)

16. Steganography In Audio
• Audio steganography embeds the secret message
into the music files having formats.
The different methods are:
• Low-bit encoding
• Phase coding
• Spread spectrum

17. ADVANTAGES
• It can be done faster with large number of software.
• Provides better security for sharing data in LAN,MAN & WAN.
• It is used in the way of hiding not the information but the password to
reach that information.
• Difficult to detect. Only receiver can detect.
• Can be applied differently in digital image, audio and video file.

18. APPLICATIONS
• Defence organisation: security from enemies
• Intelligence Agencies: security of person's private information
• Government Agencies: store critical data like criminal record
• Smart identity cards: personal information is embedded into photo
• Medical: patient's details are embedded within image

19. Negative Aspects
• The confidentiality of information is maintained by the
algorithms,
and if the algorithms are known then this technique is of no use.
• Huge number of data results in huge file size, so some one can
suspect about it.
• Password leakage may occur and it leads to the unauthorized
access of data.
• If this technique is gone in the wrong hands like hackers can be
very much dangerous for all.

20. FUTURE SCOPES
• Specifically, you can embed all your good/bad memory in each snap
shot of the digital photo such as photo recovery.
• If a "motion picture steganography system" has been developed in
the near future.
• A keyword based movie-scene retrieving system will be
implemented.
• An HTML source file has lot of free space e.g. bank webpage, online
transaction etc.
• With a painting/art work the original artist detail can be hidden.
• With a X-ray copy the details of a his/her patient can be stored.

21. CONCLUSION
• Though Steganography is not implemented in wider ways but it can be
the best security tool.
• The main problem of today’s world is to secure their data confidentially,
the techniques used currently are not considered the best which can only
be replaced by Steganography.
• The importance of Steganography has not been realized to that stage
where it is preferred over its close rival "Encryption".
• New techniques are being discovered and implemented.

22. THANK YOU

23. Any Queries