Steganography Presented by: Chudasama Khushbu VIII sem-CSE 10ECACS003 Presentation On
Steganography
Presented by:Chudasama KhushbuVIII sem-CSE10ECACS003
Presentation On
Outlines
What is Steganography?
History of Steganography
Steganography, Cryptography & Watermarking
Types of Digital Steganography
Image based Technique
Security
Use of steganography
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
Tattoos on shaved heads
Wax-covered tablets
Microdots – shrunken pictures
Invisible Inks - milk, fruit juice, urine
History of Steganography
STEGANOGRAPHY TERMS
Carrier or Cover File
Stego-Medium
Embedded or Payload
Steganalysis
Security Systems
Cryptography
Information Hiding
Steganography
Watermarking
Steganography, Cryptography&Watermarking
Major two branches of information hiding, Steganography and Watermarking.
Steganography and Cryptography are closely related.
The difference is in their goals.
Conti..
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
Cryptography Tech
Cipher Text
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.
Steganography
How It Works
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..
Steganography
Encode message
Decode message
STEGANOGRAPHY STEPS
ENCODING
Step 3
• Steganographic data
Step 2
• Encode embedded data with cover data
Step1
• Prepare cover data
DECODING
• Steganographic Data
Step1
• Decode Plain info
Step 2• Embedded
data obtained
Step 3
Hiding a Message inside Text
Hiding a Message inside Images• Most popular technique
Hiding a Message inside Audio and Video Files
Types of Steganography
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
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.
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.
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).
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
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.
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)
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.
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
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
Governments
Businesses: Digital Watermarking
Individuals
Uses of Steganography
ILLEGAL USAGE
HACKERS
TERRORISTS
CRIMINALS
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
Live Demo:
QUERIES