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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.