Steganography is the art and science of hiding messages within other carriers or cover files so that the existence of the message is concealed. Some common carriers used for steganography include text, images, audio, and video files. The document discusses the history of steganography and how it differs from cryptography and digital watermarking. It also describes various techniques for hiding messages in digital files such as least significant bit insertion in images and modifying text files by capitalizing random letters.

1. Steganography
Presented by:
Chudasama Khushbu
VIII sem-CSE
10ECACS003
Presentation
On

2. Outlines
What is Steganography?
History of Steganography
Steganography, Cryptography & Watermarking
Types of Digital Steganography
Image based Technique
Security
Use of steganography

3. 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
Carrier: text, image, video, audio, etc
Steganography

4. Tattoos on shaved heads
Wax-covered tablets
Microdots – shrunken pictures
Invisible Inks - milk, fruit juice, urine
History of Steganography

5. STEGANOGRAPHY TERMS
Carrier or Cover File
Stego-Medium
Embedded or Payload
Steganalysis

6. Security
Systems
Cryptography
Information
Hiding
Steganography Watermarking
Steganography, Cryptography
&Watermarking

7. Major two branches of information
hiding, Steganography and Watermarking.
Steganography and Cryptography are closely
related.
The difference is in their goals.
Conti..

8. Cryptography
• Science of writing in secret
code and is an ancient art.
• Achieve security by encoding
messages to make them non-
readable.
• Process to convert Plain Text
in to Cipher Text.
• Plain Text: Clear Text
• Cipher Text: Codified Text
Plain Text
Cryptogra
phy Tech
Cipher
Text

9. Watermarking
• Used to verify the identity and
authenticity of the owner of a digital
image.
• Process in which the information which
verifies the owner is embedded into the
digital image or signal. Signals could be
either videos or pictures or audios.
• Two types; visible watermarking and
invisible watermarking.

11. Steganography
How It Works

12. Main difference is..
 Cryptography: although encypted and
unreadable,the existence of
data is not hidden
 Steganography: no knowledge of the existence
of the data
 Watermarking: extending the file with extra
information
Conti..

13. STEGANOGRAPHY STEPS

14. ENCODING
Step
3
• Steganographic
data
Step
2
• Encode
embedded data
with cover data
Step1
• Prepare
cover
data

15. DECODING
• Steganographic
Data
Step1
• Decode
Plain info
Step 2
• Embedded
data
obtained
Step 3

16. Hiding a Message inside Text
Hiding a Message inside Images
• Most popular technique
Hiding a Message inside Audio and Video
Files
Types of Steganography

17. Hiding a Message inside Text
 Partially effective
 Example:
randoM capitalosis is a rarE disEase ofTen
contrAcTed by careless inTernet users. tHis sad
illnEss causes the aFfected peRsON To randomly
capitalize letters in a bOdy oF texT. please
do not confuse this disease witH a blatant
attEmpt aT steganogRAPhy.
Reveals: MEET AT THE FRONT OF THE TRAP

18. Hiding a Message inside Images
 Most widely used medium today.
 Takes advantage of our limited visual
perception of colors.
 This field is expected to continually grow as
computer graphics power also grows.

19. Image Attributes:
• Digital images are made up of pixels.
• The arrangement of pixels make up the
image’s “raster data”.
• 8-bit and 24-bit images are common.
• The larger the image size, the more
information you can hide.

20. Hiding a Message inside Audio and Video
Files
• Embedding secret message in to digital sound
is known as audio & video steganography.
• Large amount of data that can be hidden inside.
• Hard to recognize because of the continuous
flow of information (moving stream of images
and sound).

21. The most common approaches to information
hiding in images are:
 Least significant bit (LSB) Insertion
 Masking and Filtering Techniques
 Algorithms and Transformations
Image based Technique

22.  Least Significant Bit (LSB) Insertion
 Most popular technique when dealing with images.
 Replaces least significant bits with the message to be
encoded.
 It is best to use images with “noisy areas” – areas
with ample color variation and without large areas of
solid color.
 Requires on average that only half the bits in image
be changed.

23. Example:
 example shows how the letter A can be
hidden in the first eight bytes of three
pixels in a 24-bit image.
Pixels:
(00100111 11101001 11001000)
(00100111 11001000 11101001)
(11001000 00100111 11101001)

24. A: 10000001
Result:
(00100111 11101000 11001000)
(00100110 11001000 11101000)
(11001000 00100111 11101001)
 Only three bits that were actually altered.
A only requires eight bytes to hide it in, the ninth
byte of the three pixels can be used to hide the next
character of the hidden message.

25.  Masking and Filtering
• Uses..
 Digital Watermarking – provides identification
pertaining to the owner;
I.e. license or copyright information
- Invisible & Visible
 Fingerprinting – provides identification of the user;
used to identify and track illegal use of content

26. Confidentiality: any unauthorized person does
not know that sensitive data exists
Survivability: verifing that the data does not get
destroyed in the transmission
No detection: cannot be easily found out that the
data is hidden in a given file
Visibility: people cannot see any visible changes to
the file in which the data is hidden
Security

27. Governments
Businesses: Digital Watermarking
Individuals
Uses of Steganography

28. ILLEGAL USAGE
HACKERS
TERRORISTS
CRIMINALS

29. U.S. officials said on
5 February 2001 that
Late. Osama bin
Laden was posting
instructions for
terrorist activities.
He was master in
this technology.
The 9/11 attack
heightened our
awareness of
steganography. It is
well published that
Bin Laden and his
terrorist cells use
steganography for
communications

30. Live Demo:

31. QUERIES