STEGANOGRAPHY &WATERMARKING

CSG252 FINAL PROJECT

By Zina Saadi & Shivani Sahi

(Dec,2004)

Motivation for the Project

• Advanced application in internet

• Efficiency in protecting copyright and seals (watermarking)

• Efficient techniques for sending confidential information and messages .

What is Steganography?

• Information Hiding

• The communication itself is invisible

• Supplements Cryptography

Steganography vs. Cryptography

• Presence of communication is hiddenin Steganography

• In cryptography,the communication is made unintelligible to the people unaware of the required keys.

Diagrammatic representation

Mediums &Techniques

• Mediums –text, audio, video and digital images

• 4 methods-

• Least Significant Bit Insertion

• Algorithms and Transformations

• Redundant Pattern Encoding

• Spread Spectrum Method

General Applications of Steganography

• Copyright Protection and Owner Identification

• Data Authentication

• Data Hiding

• Medical Safety

What is Watermarking

• Information Hiding-methods that hide information in a data object .

• May or may not be apparent to a viewer.

• Should be impossible to remove a watermark without degrading the quality of the data object.

Requirements (Properties) of a watermark

• Unobstrusive

• Robust

Geometric Processes

Common Signal Processing

Collusion and Forgery

• Universal

• Unambiguous

Implementation

• Watermarking

• Extraction

Advantages of the implemented Technique

• Technique is immune to geometric processes such as rotation, scaling, translation .

• Size of the watermark image and the original image is not the same

Disadvantages of the implemented technique

• Value of alpha based on a comparative view of the color-scale of the original and the watermark.

• Values of alpha

0.1

0.01

0.001

Conclusion

• Supplement to Cryptography ,not a replacement

• Extensive use in hiding confidential information

• Internet usage in the current age.