Steganography is the art and science of hiding data within other data. It works by embedding secret messages within images, audio files or other cover objects. Unlike cryptography, which encrypts messages to hide their meaning, steganography conceals the very existence of the message. Some key points about steganography include its Greek origins meaning "covered writing", the use of techniques like least significant bit insertion to hide data in image files, and its applications for copyright protection and transporting secret documents.

1. STEGANOGRAPHY
“The Art Of Hiding Data”
Department of Computer Science & Engg.
Gandhi Institute for Technological Advancement(GITA), Bhubaneswar.

2. OVERVIEW
• What is Steganography?
• History
• Steganography vs Cryptography
• Types of Steganography
• Basic Steganography Model
• Techniques for using Image Steganography
• LSB Algorithm
• Steganography And Cryptography
• Application
• Conclusion 2

3. • The word steganography is of Greek origin and means "concealed writing" from the Greek
words steganos meaning "covered or protected", and graphein meaning "writing".
• 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 main objective of Steganography is mainly concerned with the protection of contents of the
hidden information.
What is Steganography
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4. • The first recorded uses of steganography can be traced back to 440 BC where wax tablets were
used to write message.
• Ancient Chinese wrote messages on fine silk, which was then crunched into a tiny ball and
covered in wax.
• During Second World War a technique was developed to shrink photographically a page of text
into a dot less than one millimeter in diameter
History Of Steganography
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5. Steganography VS Cryptography
STEGANOGRAPHY CRYPTOGRAPHY
Steganography prevents discovery of the
very existence of communication
Encryption prevents an unauthorized
party from discovering the contents of a
communication
Technology still being develop for certain
formats
Most of algorithm known by all
Once detected message is known Strong current algorithm are resistant to
attacks ,larger expensive computing
power is required for cracking
Steganography does not alter the structure
of the secret message
Cryptography alter the structure of the
secret message
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6. • Text Steganography : Text steganography can be achieved by altering the text formatting, or by
altering certain characteristics of textual elements
• Image Steganography : Images are used as the message carriers. Images are the most popular
cover objects used for steganography.
• Audio Steganography : In audio steganography, secret message is embedded into digitized audio
signal which result slight altering of binary sequence of the corresponding audio file.
Types Of Steganography
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7. Basic Steganography Model
Secret
message
Cover
Stegosystem
encoder
Key
Stegosystem
decoder
Stego object
Secret
Message
Communication
Channel
Stego Object
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8. • By using LSB(Least Significant Bit algorithm)
• Masking and Filtering
• Algorithms and Transformation
Techniques for using Image Steganography
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9. • Least significant bit (LSB) insertion is a common, simple approach to embedding information in
a cover image.
• The least significant bit of some or all of the bytes inside an image is changed to a bit of the
secret message.
• When using a 24-bit image, a bit of each of the red, green and blue colour components can be
used, since they are each represented by a byte.
• In its simplest form, LSB makes use of BMP images, since they use lossless compression.
LSB Algorithm
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10. What Images are made up of?:-
Images 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.
11111000 11001001 00000011
• The difference between two colors that differ by one bit in either one red, green or blue value is
impossible detect for a human eye.
• This means we can overwrite the last bit in a byte without affecting the colors it appears to be.
Cont…
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11. • Example:
We can use images to hide things if we replace the last bit of every color’s byte with a
bit from the message.
Message A-01000001
Image with 3 pixels
Pixel 1: 11111000 11001001 00000011
Pixel 2: 11111000 11001001 00000011
Pixel 3: 11111000 11001001 00000011
Cont…
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12. Now we hide our message in the image.
Message: 01000001
Pixel 1: 11111000 11001001 00000010
Pixel 2: 11111000 11001000 00000010
Pixel 3: 11111000 11001001 00000011
Cont…
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13. Steganography And Cryptography
Plain Text Encryption Cipher Text Cover Image
Stego Images
Cipher TextDecryptionPlain Text
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14. • Transport Highly Private Documents between International Governments.
• Copyright protection: A secret copyright notice or watermark can be embedded inside an image
to identify it as intellectual property.
• Feature tagging: An article, illustration, or poster and other brief explanation elements can be
embedded inside an image.
• Usage in modern printers.
Application
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15. • Security is an important issue while transferring the data using internet because any unauthorized
individual can hack the data and make it useless or obtain information un- intended to him.
• Hiding a message with steganography methods reduces the chance of a message being detected.
• In and of itself, steganography is not a good solution to secrecy, but neither is simple substitution
and short block permutation for encryption. But if these methods are combined, we have much
stronger encryption routines.
Conclusion
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16. THANK YOU