1. Introduction to Steganography
BSIT-7th Instructor: Inam Ul Haq
Steganography, Network Security, University of Okara

2. Table of content
Information Hiding Steganography History Fields applied to Information Hiding Basic Terminologies Steganalysis Some Applications Some Tools Steganography Techniques
Steganography, Network Security, University of Okara

3. Information Hiding
F. A. P. Petitcolas, R. J. Anderson, M. G. Kuhn, “Information Hiding – A Survey”, Proceedings of the IEEE,
special issue on protection of multimedia content, 87(7): , July 1999
Steganography, Network Security, University of Okara

4. Information Hiding
Information Hiding is a branch of computer science that deals with concealing the existence of a message
It is related to cryptography whose intent is to render messages unreadable except by the intended recipients
It employs technologies from numerous science disciplines:
Digital Signal Processing (Images, Audio, Video)
Cryptography
Information Theory\Coding Theory
Data Compression
Human Visual/Auditory perception
There are four primary sub-disciplines of Information Hiding
Steganography
Watermarking
Covert Channels
Anonymity
Steganography, Network Security, University of Okara

5. Steganography Steganography means “covered writing”
A Greek word steganos means covered, protected or concealed
Definition: It is concealing any file, image, audio or video within another file.
Most frequently, steganography is applied to images, but many other data or file types are possible
Audio
Video
Text
Executable programs
Links
Steganography, Network Security, University of Okara

6. History
The concept of message hiding is not new – it’s been around for centuries
A Greek shaved the head of a slave, wrote a message, then waited for the hair to grow back before sending the slave to his destination
Steganography (in the form of invisible ink) was used by Washington in the Revolutionary War
Prior to the Civil War, quilts were sewn with special patterns to tell escaping slaves which direction to go and what to do
In the 1980’s, some of Margaret Thatcher’s cabinet documents were leaked to the press. She ordered that the word processors being used by government employees, encode their identity in the word spacing of the documents
Steganography, Network Security, University of Okara

7. Fields Applied to Information Hiding
Information Theory/Coding Theory
Digital Signal Processing
Discrete Fourier Transform/Discrete Cosine Transform
Image/Audio/Video Processing
Data Compression
Cryptographic Principles
Discrete Math
Cryptographic Hashing
Data Networks
The Human Visual System/Human Auditory System
Capabilities and limitations
Steganography, Network Security, University of Okara

8. Basic Terminology The data to be hidden:
Plaintext / Secret message / Stego-message / Embedded data
The data which will have a stego-message embedded in it:
Covertext / Cover-Object /
Cover-Image\Cover-Audio\Cover-Video
Target file
The key used to make the stego-message secure
Stego-Key / Secret Key / Key
The file with the steganography-message embedded
Stegotext / Stego-Object /
Stego-Image\Stego-Audio\Stego-Video
Steganography, Network Security, University of Okara
Steganography, Network Security, University of Okara

9. Watermarking Anonymity
Watermarking is very similar to steganography in that one of its goals is to not be detected
It’s primary goal is to not be able to be extracted or destroyed (at least not without destroying the cover too)
Typically, watermarking is designed to protect intellectual property rights for images, sounds, and video
If it’s easily removed or destroyed, those rights cannot be protected
There is a popular program called StirMark which does just that
Make it tamper proof
Anonymity
Anonymity is about concealing the sender and receiver of messages and this is the least studied sub-discipline of information hiding
Steganography, Network Security, University of Okara

10. Steganalysis
Steganalysis is the detection of data that has been hidden It is a cat and mouse game – as one group of researchers come up with better ways to hide stuff, another group figures out how to detect it or perhaps just destroy it
Steganography, Network Security, University of Okara

11. Applications of Information Hiding
Covert military communications
Covert police communications
Criminals have learned that police are nearby when they hear encrypted communications, so they reduce their activity for the moment
A steganographic system would prevent this detection
Digital Rights Management – protecting intellectual property such as images, music, electronic books, etc.
Embedding textual data in medical images would better ensure that the picture belongs to a particular patient
This technique could apply to personal pictures, sounds, and movies
Tamper proofing – ensuring a data file has not been changed
Steganography, Network Security, University of Okara

12. Steganography tools Anubis BMP Secrets DarkCryptTC OpenPuff OpenStego
StegFS
StegoShare
Other tools:
12 best steganography tools: software/
Steganography, Network Security, University of Okara

13. Steganography tools (contt.)
StegoShare allows embedding of large files into multiple images
Steganography, Network Security, University of Okara

14. Steganography tools (contt.)
Free tool that implements three layers of hidden data
Steganography, Network Security, University of Okara

15. Steganographic Techniques - Substitution
The most common method is to replace the Least Significant Bit (LSB) in substitution
RSA Algorithm
Hash LSB
DEF CON 16
See other techniques: df
Steganography, Network Security, University of Okara

16. Exercise 1- What is covert Channel?
2- Write a detail note on Anonymity.
3- Watermarking
4- Fingerprinting
5- Explore StirMark
6- What are different steganographic techniques?
7- Can you embed secret message into image?
Steganography, Network Security, University of Okara