1. Welcome

2. Presented By: Aryasindhu Sahu
Steganography :
A Modern
Approach To
Digital security
Syntech 2010 , SIET Dhenkanal
Presented By: Aryasindhu Sahu

3. The art of hiding information inside information.
stegos
graphia +
Steganography
Covered
Writing
The art of hiding information inside information.

4. "Since everyone can read, encoding text in neutral sentences is doubtfully effective."
SECRET INSIDE

5. Historical Facts Ancient Greeks used wax on wood
World War 2 – use of Invisible Inks
Old Paintings – symbols and signs

6. Modern Steganography Text Injection File Embedding
Digital Watermarking
Copyright Marking
Data Encryption
LSB Editing

7. Hiding Several Messages:
Deniable Cryptography
Knowledge of encrypted data
No proof how much information is stored
Digital Watermarking:
Not really hiding information
Important: Not modifiable
Uses the hiding property of Steganography
Recent: MPAA hides watermarks in movies.

8. Implementations CODEBOOK Original Document Marked Document ENCODER

9. Steganography Implementations Texts / Web ages Images Audios Videos
Digital Equipments
Implementations
Steganography

10. Implementations Texts or Web Pages Use of codebooks Layout of text
Every Nth character
Use of whitespaces and newlines
Difficult to detect and decode

11. Implementations Images Cover Images Identifying Redundant data
Replace (a subset of ) redundant bits with data

12. Implementations Audios Frequencies inaudible to human
Embedding data using LSB
Encoding musical tones

13. Implementations Videos Visible signals Using Image Steganography
Using Audio Steganography

14. Example of Image Steganography
255,0,0
, ,
255,0,1
, ,
254,1,0
, ,
Secret data is encrypted at the positions of LSB and decrypted at the recipient.
A little change in the LSB puts very less effect on the pixel.
So we are unable to identify the steganographic images.

15. Modern use of Steganography
In modern printers
Digital Images
Encryption
Document Password Protection
Website Security
Digital Watermarking
SAFDB (Steganography Application Fingerprint Database)

16. Detection Of Steganography
In Text or Web Pages
Look for (disturbing of) patterns
Odd use of language
Line heights and whitespaces

17. Detection Of Steganography
In Images
Examine color palette
Size of the image
Differences:
− Format
− Last modified date
Statistical analysis
Analyze frequency of DCT (discrete cosine transform) coefficients
Entropy of redundant data
− Hidden content higher entropy
Apply filters to steganograms
Visible representation of statistical data

18. Detection Of Steganography
In Audios
Statistical analysis
Analyze patterns in background noise
Distortions
Measure inaudible frequencies

19. Detection Of Steganography
In Videos
Look for distinguishing movements
Same techniques as with images
Same techniques as with audio

20. Defeating Steganography
Text
Images
● Change spacing ● Modify line heights, layout ● Add or remove words
● Compress with lossy compression
● Convert to different format
● Resize the image
● Modify colors
Audios
Videos
● Compress with lossy compression
● Change bit rate
● Alter / limit frequency spectrum
● Same techniques as with images
● Same techniques as with audio

21. Comparison of Secret Communication Technique
Confidentiality
Integrity
Unremovability
Encryption
Yes No
Digital Signature
Steganography
Yes/No

22. Terrorism & Steganography
Terror groups hide behind web encryption.
Uncrackable encryption is allowing terrorism.
Example :
s from Al-Qaida or Laden Group after Sept 11 attack.

23. Conclusion Seamless Security Hide data practically everywhere
Hidden Watermarking
Data Stealing reduced
Detection of Steganography
− Possible, but can be difficult
Defeating Steganography is not hard

24. QUESTIONS ?