DIGITAL WATERMARKING Shashwat Shriparv email@example.com InfinitySoft
What is Watermarking?
What is Digital Watermarking?
Behind the Technology.
Types of Watermarking.
Digital Watermarking Techniques.
Features of Digital Watermarking.
Attacks to Digital Watermarking.
Introduction Advantages ofDigital Data Copy right problemswith digital data Encryption & Decryption Problemswith Encryption & Decryption
Conventional Encryption System
Watermark What is Watermarking? “ Watermarking can be considered as a special technique of steganographywhere one message is embedded in another and the two messages are related to each other in some way. “ Example :- The presence of specific patterns in currency notes which are visible only when the note is held to light is a well known example for watermark.
Example of a conventional watermark Courtesy of Blue Spike, Inc.
Digital Watermarking is originated from Steganography
What is Digital Watermarking? “ Digital watermarking is similar to watermarking physical objects, except that thewatermarking technique is used for digital contentinstead of physical objects. “ Digital Watermark
Digital Watermark (Contn..)
In digital watermarking a low-energy signal is imperceptibly embedded in another signal. The low-energy signal is called watermark.
The main signal in which the watermark is embedded is referred to as cover signalsince it covers the watermark.
An entity called watermark key used for embedding and detecting watermark signal
Watermark key is private
Behind The Technology Sending Side … Watermark Embedding process
Water marked image
Behind The Technology Receiving Side … Watermark retrieval process
Water marked image
The Overall System The Technology Roars…
Importance Of Digital Watermarking
On-line music industry
News gathering using digital cameras
Types of Digital Watermarking. Variety Adds…
Robust & Fragile Watermarking
Visible & Invisible Watermarking
Public & Private Watermarking
Asymmetric & Symmetric Watermarking
Steganograhic & Non-Steganographic watermarking
Robust & Fragile Watermarking Robust Watermarking:-Modification of watermarked content will not affect watermark Fragile Watermarking:-Watermark get destroyed when watermarked content is modified or tampered with
Visible & Invisible Watermarking On Visiblewatermarking, contents are visible
Visible & Invisible Watermarking (Contn..) Invisible watermarking are not viewed on just looking
Public & Private Watermarking
Users of content are authorized to detect watermark
Users not authorized to detect watermark
Asymmetric & Symmetric watermarking In Asymmetric watermarkingdifferent keys used for embedding and detecting watermark
Asymmetric & Symmetric watermarking (Contn..) In symmetric watermarking same keys are used for embedding and detecting watermarks
Steganographic & Non-Steganographic Watermarking Steganographic Watermarking User unaware of the presence of a watermark eg:-Used in finger printing applications Non-Steganographic WM:- User aware of the presence of a watermark. e.g.:-User to detect piracy
Digital Watermarking Techniques
Color Separation Technique
Bit Stream Watermarking
Word Space Coding, Line Space Coding &Character Coding
LSB Watermarking Lower order bitsof selected pixels in the image are used to store watermarks Replacing lower order bitsof each pixel with higher order bit of different image
Color Separation Technique Watermark appears only in one of the color bands Used to watermark in still images Can be extended to moving images
Bit Stream Watermarking Used in audiowatermarking Data is directly inserted into compressed audio files
Word Space Coding, Line Space Coding &Character Coding Used for watermarking in text documents In word space coding, the spaces between words are altered to embed watermark code. Inline space coding the space between the lines are altered and in character coding some of the characters are imperceptibly modified (i.e., made larger, serifs enhanced, etc).
Features of Digital Watermarking
Applications of Digital Watermarking. Copy Protection Content Authentication Copyright Protection Metadata Tagging
It limits the access to copyrighted material and inhibit the copy process
Robust watermarks are used in this area
Example:-A photographic information that may be presented as evidence in court. Since digital images can be easily manipulated, there is a need to provide proof that an image has not been altered.
One of the main application
Embedding watermarks indigital photographs
Watermarks convey object specific information to users of the object.
Used to attach patient identification data to medical images, or to highlight regions of diagnostic significance.
Attacks to Digital Watermarking Stirmark Mosaic Attack
Stirmark It is tool developed totest the robustness of image marking system Stirmark is commonly produced by printers and scanners IBM researchers have recently announced a technique that defeats the stir mark attack. Detects and measures the geometric distortions in images, and removes the distortion to restore image geometry
Mosaic Attack Use of a web crawler Dividing into sub images with rendition instructions Browser will be rearranging the sub images to appear as the original Sub images will be sufficiently small that no single image on its own will contain a recognizable mark.
Conclusion DRM systems and content management are important for protection of rights of digital multimedia creations that are distributed on the Internet. Digital watermarking is an effective technique for embedding rights information in digital multimedia data. Digital watermark technology can be used in consumer electronic devices like digital still camera, digital video camera, DVD players, MP3 players, etc., for various applications like providing controlled access, preventing illegal replication and watermark embedding
Conclusion (Contd..) Digital information can easily be disseminated and copied via global networks. The future of digital watermarking relies on setting standards and creating applications so that creators of digital content can easily implement it.