[attachment=857]
ABSTRACT

Digital watermarking is an extension of steganography, is a promising solution for content copyright protection in the global network. It imposes extra robustness on embedded information. Digital watermarking is the science of embedding copyright information in the original files. The information embedded is called watermarks.

Digital watermarking doesnâ„¢t leave a noticeable mark on the content and donâ„¢t affect its appreciation. These are imperceptible and detected only by proper authorities. Digital watermarks are difficult to remove without noticeable degrading the content and are covert means in situations where cryptography fails to provide robustness.

The content is watermarked by converting copyright information into random digital noise using special algorithm that is perceptible only to the creator.

Watermarks are resistant to filtering and stay with the content as long as the original has not been purposely damaged.

1. INTRODUCTION

In recent years, the distribution of works of art, including pictures, music, video and textual documents, has become easier. With the widespread and increasing use of the Internet, digital forms of these media (still images, audio, video, text) are easily accessible. This is clearly advantageous, in that it is easier to market and sell one's works of art. However, this same property threatens copyright protection. Digital documents are easy to copy and distribute, allowing for pirating. There are a number of methods for protecting ownership. One of these is known as digital watermarking.

Digital watermarking is the process of inserting a digital signal or pattern (indicative of the owner of the content) into digital content. The signal, known as a watermark, can be used later to identify the owner of the work, to authenticate the content, and to trace illegal copies of the work.

Watermarks of varying degrees of obtrusiveness are added to presentation media as a guarantee of authenticity, quality, ownership, and source.
To be effective in its purpose, a watermark should adhere to a few requirements. In particular, it should be robust, and transparent. Robustness requires that it be able to survive any alterations or distortions that the watermarked content may undergo, including intentional attacks to remove the watermark, and common signal processing alterations used to make the data more efficient to store and transmit. This is so that afterwards, the owner can still be identified. Transparency requires a watermark to be imperceptible so that it does not affect the quality of the content, and makes detection, and therefore removal, by pirates less possible.

The media of focus in this paper is the still image. There are a variety of image watermarking techniques, falling into 2 main categories, depending on in which domain the watermark is constructed: the spatial domain (producing spatial watermarks) and the frequency domain (producing spectral watermarks). The effectiveness of a watermark is improved when the technique exploits known properties of the human visual system. These are known as perceptually based watermarking techniques. Within this category, the class of image-adaptive watermarks proves most effective.
In conclusion, image watermarking techniques that take advantage of properties of the human visual system, and the characteristics of the image create the most robust and transparent watermarks.

1.1 THE DIGITAL WATERMARK

Digital watermarking is a technology for embedding various types of information in digital content. In general, information for protecting copyrights and proving the validity of data is embedded as a watermark.

A digital watermark is a digital signal or pattern inserted into digital content. The digital content could be a still image, an audio clip, a video clip, a text document, or some form of digital data that the creator or owner would like to protect. The main purpose of the watermark is to identify who the owner of the digital data is, but it can also identify the intended recipient.

Why do we need to embed such information in digital content using digital watermark technology? The Internet boom is one of the reasons. It has become easy to connect to the Internet from home computers and obtain or provide various information using the World Wide Web (WWW).

All the information handled on the Internet is provided as digital content. Such digital content can be easily copied in a way that makes the new file indistinguishable from the original. Then the content can be reproduced in large quantities.

For example, if paper bank notes or stock certificates could be easily copied and used, trust in their authenticity would greatly be reduced, resulting in a big loss. To prevent this, currencies and stock certificates contain watermarks. These watermarks are one of the methods for preventing counterfeit and illegal use.

Digital watermarks apply a similar method to digital content. Watermarked content can prove its origin, thereby protecting copyright. A watermark also discourages piracy by silently and psychologically deterring criminals from making illegal copies.

Principle of digital watermarks

A watermark on a bank note has a different transparency than the rest of the note when a light is shined on it. However, this method is useless in the digital world.

Currently there are various techniques for embedding digital watermarks. Basically, they all digitally write desired information directly onto images or audio data in such a manner that the images or audio data are not damaged. Embedding a watermark should not result in a significant increase or reduction in the original data.

Digital watermarks are added to images or audio data in such a way that they are invisible or inaudible Ñ unidentifiable by human eye or ear. Furthermore, they can be embedded in content with a variety of file formats. Digital watermarking is the content protection method for the multimedia era.

Materials suitable for watermarking

Digital watermarking is applicable to any type of digital content, including still images, animation, and audio data. It is easy to embed watermarks in material that has a comparatively high redundancy level ("wasted"), such as color still images, animation, and audio data; however, it is difficult to embed watermarks in material with a low redundancy level, such as black-and-white still images.

To solve this problem, we developed a technique for embedding digital watermarks in black-and-white still images and a software application that can effectively embed and detect digital watermarks.

Structure of a digital watermark

The structure of a digital watermark is shown in the following figures.





The material that contains a digital watermark is called a carrier. A digital watermark is not provided as a separate file or a link. It is information that is directly embedded in the carrier file. Therefore, simply viewing the carrier image containing it cannot identify the digital watermark. Special software is needed to embed and detect such digital watermarks. Kowa 's SteganoSign is one of these software packages.

Both images and audio data can carry watermarks. A digital watermark can be detected as shown in the following illustration.


1.2 THE IMPORTANCE OF DIGITAL WATERMARKS

The Internet has provided worldwide publishing opportunities to creators of various works, including writers, photographers, musicians and artists. However, these same opportunities provide ease of access to these works, which has resulted in pirating. It is easy to duplicate audio and visual files, and is therefore probable that duplication on the Internet occurs without the rightful owners' permission.

An example of an area where copyright protection needs to be enforced is in the on-line music industry. The Recording Industry Association of America (RIAA) says that the value of illegal copies of music that are distributed over the Internet could reach $2 billion a year.

Digital watermarking is being recognized as a way for improving this situation. RIAA reports that "record labels see watermarking as a crucial piece of the copy protection system, whether their music is released over the Internet or on DVD-Audio". They are of the opinion that any encryption system can be broken, sooner or later, and that digital watermarking is needed to indicate who the culprit is.

Another scenario in which the enforcement of copyright is needed is in newsgathering. When digital cameras are used to snapshot an event, the images must be watermarked as they are captured. This is so that later, image's origin and content can be verified. This suggests that there are many applications that could require image watermarking, including Internet imaging, digital libraries, digital cameras, medical imaging, image and video databases, surveillance imaging, video-on-demand systems, and satellite-delivered video.

1.3 THE PURPOSES OF DIGITAL WATERMARKS

Watermarks are a way of dealing with the problems mentioned above by providing a number of services:
1. They aim to mark digital data permanently and unalterably, so that the source as well as the intended recipient of the digital work is known. Copyright owners can incorporate identifying information into their work. That is, watermarks are used in the protection of ownership. The presence of a watermark in a work suspected of having been copied can prove that it has been copied.
2. By indicating the owner of the work, they demonstrate the quality and assure the authenticity of the work.
3. With a tracking service, owners are able to find illegal copies of their work on the Internet. In addition, because each purchaser of the data has a unique watermark embedded in his/her copy, any unauthorized copies that s/he has distributed can be traced back to him/her.
4. Watermarks can be used to identify any changes that have been made to the watermarked data.
5. Some more recent techniques are able to correct the alteration as well.




1.4 OVERVIEW OF COPYRIGHT LAW

"In essence, copyright is the right of an author to control the reproduction of his intellectual creation" . When a person reproduces a work that has been copyrighted, without the permission of the owner, s/he may be held liable for copyright infringement. To prove copyright infringement, a copyright owner needs to prove 2 things.

1. S/he owns the copyright in the work, and
2. The other party copied the work (usually determined by establishing that the other party had access to the copyrighted work, and that the copy is "substantially similar" to the original).
In cases where it cannot be said that the owner's work and the possible illegal copy are identical, the existence of a digital watermark could prove guilt.

The damages charge can be higher if it can be proven that the party's conduct constitutes willful infringement; that is, s/he copied the work even though s/he knew that it was copyrighted (for example, copying even after having discovered a watermark in the work).


2. DIGITAL WATERMARK TYPES AND TERMS

Watermarks can be visible or invisible:
a. Visible watermarks are designed to be easily perceived by a viewer (or listener). They clearly identify the owner of the digital data, but should not detract from the content of the data.
b. Invisible watermarks are designed to be imperceptible under normal viewing (or listening) conditions; more of the current research focuses on this type of watermark than the visible type.
Both of these types of watermarks are useful in deterring theft, but they achieve this in different ways. Visible watermarks give an immediate indication of who the owner of the digital work is, and data watermarked with visible watermarks are not of as much usefulness to a potential pirate (because the watermark is visible). Invisible watermarks, on the other hand, increase the likelihood of prosecution after the theft has occurred. These watermarks should therefore not be detectable to thieves, otherwise they would try to remove it; however, they should be easily detectable by the owners.
A further classification of watermarks is into fragile, semi-fragile or robust:
a. A fragile watermark is embedded in digital data to for the purpose of detecting any changes that have been made to the content of the data. They achieve this because they are distorted, or "broken", easily. Fragile watermarks are applicable in image authentication systems.
b. Semi-fragile watermarks detect any changes above a user-specified threshold.
c. Robust watermarks are designed to survive "moderate to severe signal processing attacks".

Watermarks for images can further be classified into spatial or spectrum watermarks, depending on how they are constructed:

a. Spatial watermarks are created in the spatial domain of the image, and are embedded directly into the pixels of the image. These usually produce images of high quality, but are not robust to the common image alterations.
b. Spectral (or transform-based) watermarks are incorporated into the image's transform coefficients. The inverse-transformed coefficients form the watermarked data.
Perceptual watermarks are invisible watermarks constructed from techniques that use models of the human visual system to adapt the strength of the watermark to the image content. The most effective of these watermarks are known as image-adaptive watermarks.

Finally, blind watermarking techniques are techniques that are able to detect the watermark in a watermarked digital item without use of the original digital item.



3. EFFECTIVE DIGITAL WATERMARKS

3.1 Features of a Good Watermark

The following are features of a good watermark:
1. It should be difficult or impossible to remove a digital watermark without noticeably degrading the watermarked content. This is to ensure that the copyright information cannot be removed.
2. The watermark should be robust. This means that it should remain in the content after various types of manipulations, both intentional (known as attacks on the watermark) and unintentional (alterations that the digital data item would undergo regardless of whether it contains a watermark or not). These are described below. If the watermark is a fragile watermark, however, it should not remain in the digital data after attacks on it, but should be able to survive certain other alterations (as in the case of images, where it should be able to survive the common image alteration of cropping).
3. The watermark should be perceptually invisible, or transparent. That is, it should be imperceptible (if it is of the invisible type). Embedding the watermark signal in the digital data produces alterations, and these should not degrade the perceived quality of the data. Larger alterations are more robust, and are easier to detect with certainty, but result in greater degradation of the data.
4. It should be easy for the owner or a proper authority to readily detect the watermark. "Such decodability without requiring the original, unwatermarked [digital document or] image would be necessary for efficient recovery of property and subsequent prosecution".
Further properties that enhance the effectiveness of a watermarking technique, but which are not requirements are:
5. Hybrid watermarking refers to the embedding of a number of different watermarks in the same digital carrier signal. Hybrid watermarking allows intellectual property rights (IPR) protection, data authentication and data item tracing all in one go.
6. Watermark key: it is beneficial to have a key associated with each watermark that can be used in the production, embedding, and detection of the watermark. It should be a private key, because then if the algorithms to produce, embed and detect the watermark are publicly known, without the key, it is difficult to know what the watermark signal is. The key indicates the owner of the data.


It is of interest to identify the properties of a digital data item (the carrier signal) that assist in watermarking:

1. It should have a high level of redundancy. This is so that it can carry a more robust watermark without the watermark being noticed. (A more robust watermark usually requires a larger number of alterations to the carrier signal).
2. It must tolerate at least small, well-defined modifications without changing its semantics.







4. THE WATERMARKING PROCESS DEMO

4.1 INVISIBLE WATERMARKING PROCESS DEMO






4.2 THE VISIBLE WATERMARKING PROCESS DEMO




5. ATTACKS ON WATERMARKS

¢ Lossy Compression: Many compression schemes like JPEG and MPEG can potentially degrade the data™s quality through irretrievable loss of data.
¢ Geometric Distortions: include such operations as rotation, translation, scaling and cropping.
¢ Common Signal Processing Operations: They include the followings.
¢ D/A conversion, A/D conversion
¢ Resampling, Requantization, Recompression
¢ Linear filtering such as high pass and low pass filtering.
¢ Addition of a constant offset to the pixel values
¢ Local exchange of pixels
¢ other intentional attacks:
¢ Printing and Rescanning
¢ Watermarking of watermarked image (rewatermarking)



6. DIGITAL WATERMARKING APPLICATIONS

Digital watermarking is rapid evolving field, this section identifies digital watermarking applications and provides an overview of digital watermarking capabilities and useful benefits to customers. The various applications are:

¢ Authentication
¢ Broadcast Monitoring
¢ Copy Prevention
¢ Forensic Tracking
¢ E-Commerce/Linking

AUTHENTICATION

Authentication identifies if content has been altered or falsified. For example digital watermarking can verify authenticity and identify counterfeiting as a second layer of security for encrypted content. The presence of digital watermark and/or continuity of watermark can help ensure that the content has not been altered.


BROADCAST MONITORING

Broadcast content is embedded wit a unique identifier, and optionally, distributor information. Detectors are placed at popular markets, where broadcasts are received and processed, resulting in reports to be sent to the owner.

COPY PREVENTION

Copy prevention helps the digital watermarks to identify whether the content can be copied. It guards against unauthorized duplication.

FORENSIC TRACKING

Forensic tracking locates the source of the content. The key advantage of digital watermarking is that it enables tracking of the content to where it leaves an authorized path.

E-COMMERCE/LINKING

The digital watermarking enables the user to purchase or access information about the content, related content, or items with in the content.

7. WATERMARKING SOFTWARE&SREVICES

1. Alpha-Tec: watermarking software for copyright protection and infringement tracking.
2. Digimarc: For document verification, copyright protection, embedded messages and more.
3. Stegnosign: For creating, embedding and detecting watermarks.
4. Signum: Allow digital fingerprints to be embedded into grahics, audio, video e.t.c.
5. MediaSec: Provide software for various media types, partial encryption, and internet tracking.




8. CONCLUSION

Digital watermarks have been used in the last few years to protect the ownership of digital data. Various techniques developed make use of the human audio-visual system. Legitimate business and webmasters have nothing to fear from copyright law or new form of on-line enforcement technology found in digital watermarks and tracking services. By using audio files and images only when they have obtained permission of the appropriate owner, webmasters should be free to continue making their sites audio visually appealing.


9. REFERENCES

1. Electronics For You
2. ewatrmark.com
3. altavita.com
4. digitalwatermarking.com







CONTENTS

1. INTRODUCTION
1.1 THE DIGITAL WATERMARK
1.2 THE IMPORTANCE OF DIGITAL WATERMARKS
1.3 THE PURPOSES OF DIGITAL WATERMARKS
1.4 OVERVIEW OF COPYRIGHT LAW
2. DIGITAL WATERMARK TYPES AND TERMS
3. EFFECTIVE DIGITAL WATERMARKS
4. THE WATERMARKING PROCESS DEMO
4.1 INVISIBLE WATERMARKING PROCESS DEMO
4.2 THE VISIBLE WATERMARKING PROCESS DEMO
5. ATTACKS ON WATERMARKS
6. DIGITAL WATERMARKING APPLICATIONS
7. WATERMARKING SOFTWARE&SREVICES
8. CONCLUSION
9. REFERENCES



ACKNOWLEDGEMENT

I express my sincere gratitude to Dr. Agnisarman Namboodiri, Head of Department of Information Technology and Computer Science, for his guidance and support to shape this paper in a systematic way.

I am also greatly indebted to Mr. Saheer H. and
Ms. S.S. Deepa, Department of IT for their valuable suggestions in the preparation of the paper.

In addition I would like to thank all staff members of IT department and all my friends of S7 IT for their suggestions and constrictive criticism.

[attachment=1354]

[attachment=1943]

ABSTRACT
The progress in multimedia storage and transmission technology has allowed storing and transmitting an ever increasing amount of information in the digital format. This possibility has greatly expanded by the advent of the World Wide Web (WWW). However the ease of copy and reproducing digital data is likely to encourage violation of Copyright © rules. Digital watermarking represents a valid solution to the above problem, since it makes possible to identify the source, author, creator, owner, distributor, or authorized consumer of digitized images video recordings or audio recordings. In digital watermarking also referred to as simply watermarking, a pattern of bits is inserted into a digital image, audio or video file that identifies the file's copyright information (author, rights, etc). The purpose of digital watermarks is to provide copyright protection for intellectual property that is in the digital format. Unlike printed watermarks, which are intended to be somewhat visible, digital watermarks are designed to be completely invisible or in the case if audible clip, inaudible. Moreover, the actual bits representing the watermarks must be scattered throughout the fde in such a way that they cannot be identified and manipulated. And finally, the digital watermark must be robust enough so that it can withstand normal changes to the file.
There are a number of companies offering competing technologies. All of them work by making the watermark appear as noise that is, random data exists in most digital files anyway. To view a watermark you need a special program that knows how to extract the watermarked data.
INTRODUCTION
Digital watermark is a promising solution for copyright protection in the global network. To put into words, digital watermarking is the art and science of embedding copyright information in the original files. The information embedded is called 'watermarks'.
Digital watermarks do not leave a noticeable mark on the content and do not affect its appearance. Theses are imperceptible and can be detected only by proper authorities. Digital watermarks are difficult to remove without noticeably degrading the content. The content is watermarked by converting copyright information into random digital noise using a special algorithm that is perceptible only to then content creator and can be read only by using the appropriate reading software.
These stay with the content as long as the original has not been purposely degraded. Why do we need to embed such information in digital content using digital watermarking technology The internet boom is one of the reasons. It has become easy to connect to the internet from home computers and obtain or provide various information using the World Wide Web (WWW).
All the information handled on the internet is provided as digital content. Such digital content can be easily copied in a way that makes the new fde indistinguishable from the original. Then the content can be reproduced in large quantities.
For example, if paper bank notes or stock certificates could be easily copied and used, trust in their authenticity would greatly be reduced, resulting in a big loss. To prevent this, currencies and stock certificates contain watermarks. These watermarks are one of the methods for preventing counterfeit and illegal use.
Digital watermarks apply a similar method to digital content. Watermarked content can prove its origin, thereby protecting copyright. A watermark also discourages piracy by silently and psychologically deterring criminals from making illegal copies.
PRINCIPLE OF DIGITAL WATERMARKING
A watermark on a bank note has a different transparency than the rest of the note when a light is shined on it. However, this method is useless in the digital world.
Currently there are various techniques for embedding digital watermarks. Basically, they all digitally write desired information directly into images or audio data in such a way that images or audio data are not damaged. Embedding a watermark should not result in a significant increase or reduction in the original data. Digital watermarks are added to images or audio data in such a manner that they are invisible and inaudible N unidentifiable by human eye or ear. Furthermore, they can be embedded in content with a variety of file formats. Digital watermarking is the content protection method for the multimedia era.
WHAT IS DIGITAL WATERMARK
There is an increasing need for software that allows for protection of ownership rights and it is in this context where watermarking techniques come to our help. Perceptible marks of ownership or authenticity have been around for centuries in the form of stamps, seals, signatures or classical watermarks; nevertheless, given current data manipulation technologies, imperceptible digital watermarks are mandatory in most applications. A digital watermark is a distinguishable piece of information that is adhered to the data that is intended to be protected. This means that it should be very difficult to extract or remove the watermark from the watermarked object. Since watermarking can be applied to various types of data, the imperceptibility constraint will take different forms, depending on the properties of the recipient (i.e., human senses in most practical cases).
In addition to the imperceptibility constraint there are some desirable characteristics that a watermark should possess, which are somewhat related to the so-called robustness issue. The watermark must be difficult (hopefully impossible) to remove. The attempt to destroy the mark by adding noise should result in degradation of the data perceptual content before the watermark is lost. First, the watermark should be resilient to standard manipulations of unintentional as well as intentional nature. Second, it should be statistically irremovable, that is a statistical analysis should not produce any advantage from the attacking point of view. Finally, the watermark should withstand multiple watermarking to facilitate traitor tracing.
Watermark contains information that must be unique otherwise the owner cannot be identified uniquely. Watermark uses secret keys o map information to owners, although the way this mapping is actually performed considerably differs from what is done in cryptography, mainly because the watermarked object should keep its intelligibility. In most applications embedment of additional information is necessary. This information includes:-
¢ identifiers of the owner
¢ identifiers of the recipient or distributor
¢ transaction dates
¢ serial numbers
which play a crucial role in adding values to the watermarking products.
Digimarc, the self-described "leader in digital watermark technology", describes the process this way: "A digital watermark is invisible to the naked eye. It hides in the naturally occurring variations throughout an image. Imbed a digital watermark in your images and you create a copyright communication device. Anyone who views your watermarked image containing your unique identifier will know who you are and how to contact you".
TYPES OF WATERMARK
Visible watermarks: Visible watermarks are an extension of the concept of logos. Such watermarks are applicable to images only. These logos are inlaid into the image but they are transparent. Such watermarks cannot be removed by cropping the centre part of the image. They are protected against attacks such as statistical analysis.
The drawbacks of visible watermarks are degrading the quality of image and detection by visual means only. Thus, it is not possible to detect them by dedicated programs or devices. Such watermarks have applications in maps, graphics and software user interface.
Invisible watermark: It is hidden in the content. It is designed to be imperceptible under normal viewing (or listening) conditions. More of the current research focuses on this type of watermark than visible type. Invisible watermark increases the likelihood of prosecution after the theft has occurred. These watermarks should therefore not be detectable to thieves, otherwise they would try to remove it, however they should be easily detectable by owners.
Public watermark: Such a watermark can be read or retrieved by anyone using the specialized algorithm. In this sense, public watermarks are not secure. However public watermarks are useful for carrying IPR information. They are good alternatives to labels.
Private watermark: They are also known as secure watermarks. To read or retrieve such a watermark, it is necessary to have the secret key.
Fragile watermark: Are also known as tamper-proof watermark. Such watermarks can be destroyed by data manipulation. This kind of watermark is embedded in
Digital Watermarking digital data for the purpose of detecting any changes that have been made to content of the data. Fragile watermarks are applicable in image authentication systems.
Perceptual watermark: It exploits the aspects of human sensory system to provide invisible yet robust watermark. Such watermarks are also known as transparent watermarks that provide extremely high quality contents.
Bit stream watermarking: The term is sometimes used for watermarking of compressed data such as video.
Text document watermarking: Text document is a discrete information source. In discrete sources cannot be modified. Thus, generic watermarking schemes are not applicable. The approaches for text watermarking are hiding watermark information in semantics and hiding watermark in text format.
In semantic based watermarking, the text is designed around the message to be hidden. Thus, misleading information covers watermark information.
By text format, we mean layout and appearance. Techniques used for this
are:-
¢ Line shift coding - single lines of document are shifted upward or downward in very small amounts. The watermark information is encoded in the way lines are shifted upwards or downwards. Watermark recovery is simple because a line space in normal text is uniform.
¢ Word shift coding - words are shifted horizontally in order to modify the spacing between consecutive words. While detecting the watermark, the original word spacing data is required because normally word spacing is variable.
¢ Feature coding - feature of some characters are modified. In a typical case,
the length of end lines to characters like b,c,d,h are modified. While
detecting the watermarks, the original lengths are known.
SOME EXAMPLES OF VISIBLE WATERMARKING
STRUCTURE OF A TYPICAL WATERMARKING SYSTEM
Every watermarking system consists at least of two different parts:-
1. Watermark generation and embedding unit
2. Watermark detection and extraction unit
WATERMARK GENERATION AND EMBEDDING UNIT
Generation of watermark is an important stage of process. Watermark contains information that must be unique otherwise the owner cannot be identified uniquely. Imagine two companies using identical watermarks, it would be impossible to prove which company the rightful author of a file belonged to. The most common method of generation is to consult a trusted third party and a watermark is generated guaranteeing uniqueness. The third party would typically be a copyright authority or watermark specialist who would store a database of all its known clients. If a product is copied without authorization and the matter is taken to the court then this authority is consulted to identify the original owner. This is done by extracting the watermark. An example of one such company is Digimarc.
The structure of a digital watermark is shown below.
Original image (carrier)
Copyrights, Production Dale, ID
etc.
Watermark information
The material that contains a digital watermark is called a carrier. A digital watermark is not provided as a separate file or a link. It is information that is directly embedded in the carrier file. Therefore, the digital watermark cannot be
Digital Watermarking identified by simply viewing the carrier image containing it. Special software is needed to embed and detect such digital watermarks. Kowa's SteganoSign is one of these software packages.
HIDDEN INFO
SEC RE'l KEY
PERCEPTUAL ANALYSIS
WATERMARK GENERATION
WATERMARK INSERTION UNIT
This figure shows the embedding unit for still images. The unmarked image is passed through a perceptual analysis block that determines how much a pixel can be altered so that the resulting watermarked image is indistinguishable from the original. This takes into account the human eye sensitivity to changes in flat areas and its relatively high tolerance to small changes in edges. After this so called perceptual mask has been computed, the information to be hidden is shaped by this mask and spread all over the original image. This spreading technique is similar to the interleaving used in other applications involving coding, such as compact disc storage, to prevent damage of the information caused by scratches or dust. In our case, the main reason for this spread-in is to ensure that the hidden information survives cropping of image. Moreover, the way this spreading is performed depends on the secret key, so it is difficult to recover the hidden information if one is not in possession of this key. Finally, watermark is added to the original image. The higher capacity areas for hiding information correspond to the edges. These masks are computed by using some known results on how the human eye works in the spatial domain.
Watermark Embedding
Let I be the original image, Iw the watermarked image, W the watermark and f the watermark function. The watermark process can be written: Iw = I + f (I,W)
The embedding of the watermark I the image can be made according to two methods:
1. Image independent: the watermark is placed in a linear way. Then, we have f(I,W) =W and the watermarked image is Iw = I + w. See figure below. Image independent processes are very sensitive to statistical attacks.
Toy example of an independent watermark: the grey level of the marked Lena is equal to the grey level of the unmarked Lena plus the grey level of the corresponding pixel in the mark.
2. Image dependent: image information's are used in order to embed the mark in a most reliable way. For instance, some embedding methods are based on Fourier (or cosine) transforms. The watermarking function then depends on I and W.
Toy example of a dependent watermarking: the grey level added to the image depends on the grey level of the corresponding pixel in the original image and the grey level of the mark.
Insertion of the mark may be performed spatially or frequently :-
¢ Special insertion: C. Dautzberg and F.M. Boland simultaneously with G. Caronni have introduced a technique based on the modification of pixels blocks depending on the bits in the mark to be written. For instance, if the bit I of a mark is equal to 1, then all the pixels in the block are increased by 1. while decreased by 1 if the bit is 0. a patchwork method had been proposed by Bender, Gruhl, Morimoto and Lu : it is based on some statistical properties of the image.
¢ Frequential insertion : the basic idea comes from E. Koch and J. Zhao who used the DCT transform of the jpeg compression scheme. Other approaches have been proposed by Ingemar J.Cox and al. their idea is to work on the FFT/DCT image and insert the watermark in important frequency regions, such that the watermark is spread over all the pixels of the image.
The association between cryptographic schemes and mark embedding process is extremely important in order to obtain reliable watermarking systems. Conventional cryptography as well as most embedding process alone cannot ensure the basic aim of watermarking, which is to protect data against counterfeiting. Usually, a private key (private watermark) is used in the embedding process. This
Digital Watermarking helps to collusion attacks (several watermarked images with different marks are used).
WATERMARK DETECTION AND EXTRACTION UNIT
A digital watermark can be detected as shown in the following illustration.
Still in its infancy, digital watermark technology will continue to be improved. Kowa will always maintain a leadership role by actively developing and introducing the latest and the best digital watermark technology in the industry.
SECRET KEY
WATERMARK EIX
PERCEPTUAL ANALYSIS
WATERMARK DETECTION
WATERMARK EXTRACTION
(YES/NO)
HIDDEN INFO
SECRET KEY
WATERMARK DETECTION AND EXTRACTION UNIT
This figure shows the typical configuration of a watermark detection and extraction unit. Watermark detection involves deciding whether a certain image has been watermarked with a given key. Watermark detector produces a binary output. Important considerations here are the probability of correct detection PD (i.e., the probability of incorrectly deciding that a watermark is present) and the probability of false alarm PF (i.e., the probability of incorrectly deciding that an image has been watermarked with a certain key). These two measures allow us to compare different watermarking schemes: one method will be superior if a higher PD for a fixed PF is obtained. Note also that for a watermarking algorithm to be useful it must work with extremely low probabilities if false alarm. Watermark detection is usually done by correlating the watermarked image with locally generated version of the watermark at the receiver side. This correlation yields a high value when the watermark has been obtained with proper key. As we have shown, it is possible to improve performance of the detector by eliminating original image-induced noise with signal processing. It is worthy of remark that some authors propose using the original image in the detection process. Although this simplifies further treatment of
Digital Watermarking watermark in the receiver end, it is quite unrealistic for most applications, particularly those related to E-commerce. Once the presence of the watermark has been correctly detected, it is possible to extract the hidden information. The procedure is also generally done by means of a cross-correlation but in this case, an independent decision has to be taken for every information bit with a sign sheer. In fact we have also shown that this correlation structure has not been well-founded and significant improvements are achievable when image statistics are available.
This is not surprising because watermarking creates a hidden (sometimes called stenographic) channel on which information is conveyed. Extraction of the watermark allows the owner to be identified and can also be used to provide information on the intended recipient. This stage is carried out using an algorithm based on the one used to embed the original watermark. Once the watermark has been successfully extracted, it is compared to those in the database and the registered owner can be identified.
OVERVIEW OF COPYRIGHT LAW
Copyright is the right of an author to control reproduction of his intellectual creation. When a person reproduces a work that has been copyrighted, without permission of the owner he may be held liable for copyright infringement. Copyright owner needs two things:-
1. He owns copyright in work
2. Other party copied the work (usually determining by establishing that other party had access to copyrighted work and that copy is 'substantially similar' to original). In the case where it cannot be said that owner's work and possible illegal copy are identical, existence of digital watermark could prove guilt.
Damages change can be higher if it can be proven that party's conduct constitutes willful infringement; i.e. he/she copied work even though he knew that it was copyrighted.
LEGAL ISSUES
One of the main applications of watermarking is copyright defense. An image, video, text document or audio sample may be embedded with a watermark and registered with copyright authority. Watermarks are legally recognized method of proof of ownership and if copyright if infringed then the matter can be presented to the court of law. There are two classifications of watermarks depending on application.
1. Robust - survives the destructive processes like data compression, resampling, cropping and cutting and pasting.
2. Fragile - should not resist tampering or only up to a certain extent.
The appropriate keys for removal are:-
¢ Private key
¢ Detection key
¢ Public key
A private key is available only to the author and can be thought of as a flair or signature to the product, for example points being snapped to grid spacing in 3d objects or certain colors used in images. This type of watermark should not be detectable by anyone other than the original author. Public key watermarks are those that can be extracted by the public. An example of this type of key is RSA algorithm used in cryptography. These are used for verification purposes perhaps to ensure the seller is the rightful owner. Finally, the detection key is the method that is recognized in the court of law. This key is available only to the author and the trusted copyright authority and can be used to bring justice to copyright infringement. The key can be used to extract the watermark and this should uniquely identify the author.
Another application for watermarking is to trace the route of the certain files during distribution. Multiple watermarks can be embedded in media as long as saturation does not occur. At each server or router in a network, a simple watermark may be embedded in real time. These watermarks may contain an IP address or DNS name. Once a file is obtained using this method it is possible to trace the route of the file between clients. A secure piece of hardware may embed a watermark automatically, in a manner which does not remove previous watermarks. This may be helpful I the area of broadcast television. If someone rebroadcasts a satellite transmission, the watermark contained within the signal identifies the machine which carried the original signal and the perpetrator can be caught.
DISTORTIONS AND ATTACKS
In practice, a watermarked object may be altered either on purpose or accidentally, so the watermarking system should still be able to detect and extract the watermark. These distortions also introduce a degradation on the performance of the system as measured by the probabilities defined in the previous section (i.e., PD and PB would decrease for a fixed PF). For intentional attacks, the goal of the attacker is to maximize the reduction in these probabilities while minimizing the impact that his/her transformations produced on the object. This has to be done without knowing the value of the secret key used in the watermarking insertion process, which is where all the security of the algorithm lies.
Next are some of the best known attacks. Some of them may be intentional or unintentional, depending on the applications:-
Additive noise: This may stem in certain applications from the use of D/A and A/D converters or from transmission errors. However, an attacker may introduce perceptually shaped noise (thus, imperceptible) with the maximum unnoticeable power. This will typically force to increase the threshold at which the correlation detector works.
Filtering: Low pass filtering, for instance, does not introduce considerable degradation in watermarked images or audio, but can dramatically affect the performance, since spread-spectrum-like watermarks have a non negligible high frequency spectral content.
Cropping: This is a very common attack since in many cases the attacker is interested in small portions of the watermarked objects, such as parts of a certain picture or frames of a video sequence. With this in mind, in order to survive, the watermark needs to be spread over the dimensions where this attack takes place.
Compression: This is generally an unintentional attack which appears very often in multimedia applications. Practically all the audio, video and images that are currently being distributed via internet have been compressed. If the watermark is required to resist different levels of compression, it is usually advisable to perform the watermark insertion task in the same domain where the compression takes place.
Rotation and scaling: This has been the true battle horse of digital watermarking, especially because of its success with still images. Correlation-based detection and extraction fail when rotation or scaling is performed on the watermarked image because the embedded watermark and the locally generated version do not share the same spatial pattern anymore. Obviously, it would be possible to do exhaustive search on different rotation angles and scaling factors until a correlation peak is found, but this is prohibitively complex.
Statistical averaging: An attacker may try to estimate the watermark and then 'unwatermark' the object by subtracting the estimate. This is dangerous if the watermark does not depend substantially on the data. Note that with different watermarked objects it would be possible to improve the estimate by simple averaging. This is a good reason for using perceptual masks to create the watermark
Multiple watermarks: An attacker may watermark an already watermarked object and later make claims of ownership. The easiest solution is to timestamp the hidden information by a certification authority.
Compression: This is generally an unintentional attack which appears very often in multimedia applications. Practically all the audio, video and images that are currently being distributed via internet have been compressed. If the watermark is required to resist different levels of compression, it is usually advisable to perform the watermark insertion task in the same domain where the compression takes place.
Rotation and scaling: This has been the true battle horse of digital watermarking, especially because of its success with still images. Correlation-based detection and extraction fail when rotation or scaling is performed on the watermarked image because the embedded watermark and the locally generated version do not share the same spatial pattern anymore. Obviously, it would be possible to do exhaustive search on different rotation angles and scaling factors until a correlation peak is found, but this is prohibitively complex.
Statistical averaging: An attacker may try to estimate the watermark and then 'unwatermark' the object by subtracting the estimate. This is dangerous if the watermark does not depend substantially on the data. Note that with different watermarked objects it would be possible to improve the estimate by simple averaging. This is a good reason for using perceptual masks to create the watermark
Multiple watermarks: An attacker may watermark an already watermarked object and later make claims of ownership. The easiest solution is to timestamp the hidden information by a certification authority.
SOFTWARE PROTECTION
Watermark
Watermarked Date ”
Wat e r m ar k a n ci f or original data
;.:^I.gr»wjW; : ¦¦¦...! The Internet ]S
Water hi a rk
T
Se cret / Publi c key
1
Se ere! / Publi c key
Generic digital watermark embedding and detection scheme
Watermark can be a number, text or image. Secret/public key is used to enforce security of watermarked content. For secure transport of watermarked data encryption/decryption is used. Watermark can be recovered by an authorized agency having secure key, watermark and/or original data.
Software is a discrete information source. It is not allowed either to add or delete even a single bit to software. Thus, watermarking technique is not suitable for copyright protection. The basic objective of a software protection system is to ensure that the software can be distributed openly in protected (encrypted) form but can be only be used within a trusted hardware system. Such a system has provision to process owner's license restrictions and protect software as well. A user has to first obtain the license that contains information about accessing the software and decrypting key. A user may be allowed access to certain portion of software for a defined period only. After seeking a license, a user can download the encrypted software over the internet. Alternatively, the distributor can also send the software. A trusted hardware is secure hardware. It contains embedded authentication software. Thus, a user is required to present secret key before access is granted. A
simple low cost solution is to use smart card in which the secret key may be stored. A trusted hardware must also ensure that the licensed software is also protected against tampering/piracy. Executable software is aware of access control mechanism. Such software can interrogate the mechanism to determine whether a particular feature is allowed by license controlling the software. To ensure a long period of protected, it is essential that the secret information should be minimal. System security depends on storing the private decryption key in a special hardware.
APPLICATIONS
This section deals with some of the scenarios where watermarking is being already used as well as other potential applications.
Video Watermarking. In this case, most considerations made in previous section hold. However, now the temporal axis can be exploited to increase the redundancy of the watermark. Note that perhaps the set of attacks that can be performed intentionally is not smaller but definitely more expensive than for still images.
Audio watermarking. In this case, time and frequency making properties of the human ear are used to conceal the watermark and make it inaudible. The greatest difficulty lies in synchronizing the watermark and the watermarked audio file, but techniques that overcome this problem have been proposed.
Hardware/Software Watermarking. This is a good paradigm that allows us to understand how almost every kind of data can be copyright protected. If one is able to find two different ways of expressing the same information, then one bit of information can be concealed, something that can be easily generalized to any number of bits. This is why it is generally said that a perfect compression scheme does not leave room for watermarking. In the hardware context, Boolean equivalences can be exploited to yield instances that use different types of gates and that can be addressed by the hidden information bits. Software can be also protected not only by finding equivalences between instructions, variable names, or memory addresses, but also by altering the order of non-critical instructions. All this can be accomplished at compiler level.
Text Watermarking. This problem, which in fact was one of the first that was studied within the information hiding area, can be solved at two levels. At the
Digital Watermarking printout level, information can be encoded in the way the text lines or words are separated. This facilitates the survival of the watermark even to photocopying. At the semantic level (necessary when raw text files are provided), equivalences between words or expressions can be used, although special care has to be taken not to destruct the possible intention of the author.
Executable Watermarks. Once the hidden channel has been created it is possible to include even executable contents, provided that the corresponding applet is running on the end user side.
Labeling. The hidden message could also contain labels that allow for example to annotate images or audio. For instance, a movie may contain a "watermark" revealing the date of manufacture, the actors who were in the film, web sites for selling paraphernalia, as well as the owner of the movie.
Fingerprinting. This is similar to the previous application and allows acquisition devices (such as video cameras, audio recorders, etc) to insert information about the specific device (e.g., an ID number) and date of creation. This can also be done with conventional digital signature techniques but with watermarking it becomes considerably more difficult to excise or alter the signature. Some digital cameras already include this feature.
Authentication. There are two significant benefits that arise from using watermarking: first, as in the previous case, the signature becomes embedded in the message, second , it is possible to create 'soft authentication' algorithms that offer a multi valued 'perceptual closeness' measure that accounts for different unintentional transformations that the data may have suffered (an example is image compression with different levels),instead of the classical yes/no answer given by cryptography based authentication. Unfortunately, the major drawback of watermarking based authentication is the lack of public key algorithms that force either to put secret keys in risk or to resort to trusted parties. Certification is an important issue for official documents, such as identity cards or passports.
Digital Watermarking
Digital watermarking allows to mutually page link information on the
documents. That means that some information is written twice on the document: for
instance, the name of a passport owner is normally printed in clear text and is
also hidden as an invisible watermark in the photo of the owner. If anyone would intend to counterfeit the passport by replacing the photo, it would be possible to detect the change by scanning the passport and verifying the name hidden in the photo does not match any more the name printed on the passport.
Copy and Playback Control. The message carried by the watermark may also contain information regarding copy and display permissions. Then, a secure module can be added in copy or playback equipment to automatically extract this permission information and block further processing if required. In order to be effective, this protection approach requires agreements between content providers and consumer electronics manufacturers to introduce compliant watermark detectors in their video players and recorders. This approach is being taken in Digital Video Disc (DVD).
Signaling. The imperceptibility constraint is helpful when transmitting signaling information in the hidden channel. The advantage of using this channel is that no bandwidth increase is required. An interesting application in broadcasting consists in watermarking commercials with signaling information that permits an automatic counting device to assess the number of times that the commercial has =been broadcast during a certain period. An alternative to this would require complex recognition software.
DIGITAL WATERMARKING - STEERING THE FUTURE OF
SECURITY
Business of online delivery and distribution via CD/removable disks of multimedia products face huge obstacles due to unlimited perfect copying and manipulation at the user end. Digital watermarking is the technology used for copy control, media identification, tracing and protecting content owner's rights.
The internet is an open network, being increasingly used for delivery of digital multimedia contents. In the digital format, content is expressed as streams of ones and zeroes that can be transported flawlessly. The contents can be copied perfectly infinite times. A user can also manipulate these files. However, good business senses necessitates two transaction mechanisms - content protection and secure transport over the internet.
Content protection mechanism attempts to protect the rights of the content creator, distributor and user. The content owner deposits a unique description of the original to a neutral registration authority. This unique distribution may be hash value or textual description. Registration authority allots a unique identification number to the content and archives these two for future reference. This unique identification number is also conveyed to the content owner.
The content owner derives suitable parameters, usually digital watermark pertaining to this unique identification number. This mark is secretly and securely merged with original content. Watermarked content's quality is minimally degraded. Owner can also attach a 'label' that is related to a unique identification number. This label is a public notice that informs a user about the 'Intellectual Property Rights' (IPR) of the content.
The secure transportation of copyright protected content over the internet requires a secure channel between two end-points for the content transport. Cryptology is an affective solution for secure transport of copyright protected
Digital Watermarking content. The implementation of a cryptology scheme requires specialized hardware and key management system. Cryptology prevents eavesdropping and manipulation of copyrighted contents during transport over the internet.
WATERMARKING SOFTWARE AND SERVICES
1. Alphatech: watermarking software for copyright protection and infringement tracking.
2. Digimarc: for document verification, copyright protection, embedding messages etc.
3. Stegnosign: for creating, embedding and detecting watermarks.
4. Signum: Allow digital fingerprints to be embedded into graphics, audio, video etc.
5. Mediasec: provides software for various media types, partial encryption and internet tracking.
CONCLUSION
Watermarking of digital survey plans is simply a next step in the process of converting from paper to digital format that has been ongoing in all areas since the computer revolution began. Broadus noted that, "digital signature technology does a better job of protecting the integrity of a document than does a paper signature". Digital watermark is better than traditional watermarking and the stamp of a surveyor or engineer. Applications for watermarking include the ability to trace a document transferred via the internet or to store information about the author and intended recipients. The most important application however is for protection against copyright violations. Registered authorities accept watermarking as proof of ownership and this can be used in court of law. Watermark algorithms used for video streams are generally similar but embedding methods vary. This depends on which format the file is stored in. Drift compression is used in compressed video files, for example MPEG-2. This method is used to ensure that image quality remains. Watermarked frames are discarded if the bandwidth is greater than the unwatermarked version. Modulation of the inter-word spacing was found to be a common technique used to embed watermarks into text documents. This was achieved easily using Adobe acrobat. Watermarked information can be destroyed by attacks, like lossy compression, especially JPEG conversion in the images. Other recent developments in this field include the use of artificial intelligence to detect attacked watermarks.
With these improvements, watermarking is becoming an increasingly reliable method of storing important information and protection of digital documents.
REFERENCES
1. Techniques and Applications of Digital Watermarking and Content
Protection Michael Arnold, Stephen D. Wolthusen, Martin Schmucker.
Artech House Publishers, July 2003
2. digimarc.com
3. watermarker.com
4. watermarkingworld.org
5. digital-watermarking.com
6. stegoArchive.com
7. webopediaTERM/digital_watermark.html
CONTENTS
INTRODUCTION 1
¢ PRINCIPLE OF DIGITAL WATERMARKING 2
WHAT IS DIGITAL WATERMARK 3
TYPES OF WATERMARK 5
¢ SOME EXAMPLES OF VISIBLE WATERMARKING 7
STUCTURE OF A TYPICAL WATERMARKING SYSTEM 8
¢ WATERMARK GENERATION AND EMBEDDING UNIT 8
¢ WATERMARK DETECTION AND EXTRACTION UNIT 12 OVERVIEW OF COPYRIGHT LAW 15
¢ LEGAL ISSUES 15 DISTORTIONS AND ATTACKS 17 SOFTWARE PROTECTION 19 APPLICATIONS 21 DIGITAL WATERMARKING - STEERING THE FUTURE OF SECURITY 24 WATERMARKING SOFTWARE AND SERVICES 26 CONCLUSION 27 REFERENCES 28

[attachment=14263]
ABSTRACT:
A robust, computationally efficient and blind digital image watermarking in spatial domain has been discussed in this paper. Embedded watermark is meaningful and recognizable and recovery process needs only one secret image. Watermark insertion process exploits average brightness of the homogeneity regions of the cover image. Spatial mask of suitable size is used to hide data with less visual impairments. Experimental results show resiliency of the proposed scheme against large blurring attack like mean and Gaussian filtering, non linear filtering like median, image rescaling, symmetric image cropping, lower order bit manipulation of gray values and loss data compression like JPEG with high compression ratio and low PSNR values. Almost as discreetly as the technology itself, digital watermarking has recently made its debut on the geo-imaging stage.
This innovative technology is proving to be a cost-effective means of deterring copyright theft of mapping data and of ensuring the authenticity and integrity of asterisked image data. First developed around six years ago, digital watermarking is a sophisticated modern incarnation of steganography-the science of concealing information within other information. In the field of e-commerce, digital watermarking has already established itself as an effective deterrent against copyright theft of photographs and illustrations. Now digital watermarking software is finding uses within national mapping agencies and others working with asterisked images or map data. Current applications range from protecting valuable map data against copyright theft to securing photographic survey or reconnaissance images against tampering.
1. INTRODUCTION:
In the recent time, the rapid and extensive growth in Internet technology is creating a pressing need to develop several newer techniques to protect copyright, ownership and content integrity of digital media. This necessity arises because the digital representation of media possesses inherent advantages of portability, efficiency and accuracy of information content in one hand, but on the other hand, this representation also puts a serious threat of easy, accurate and illegal perfect copies of unlimited number. Unfortunately the currently available formats for image, audio and video in digital form do not allow any type of copyright protection. A potential solution to this kind of problem is an electronic stamp or digital watermarking which is intended to complement cryptographic process [1].
The technology:
Digital watermarking, an extension of steganography, is a promising solution for content copyright protection in the global network. It imposes extra robustness on embedded information. To put into words, digital watermarking is the art and science of embedding copyright information in the original files. The information embedded is called ‘watermarks’.
Digital watermarks don’t leave a noticeable mark on the content and don’t affect its appearance. These are imperceptible and can be detected only by proper authorities. Digital watermarks are difficult to remove without noticeably degrading the content and are a covert means in situations where cryptography fails to provide robustness.
The content is watermarked by converting copyright information into random digital noise using a special algorithm that is perceptible only to the content creator. Digital watermarks can be read only by using the appropriate reading software. These are resistant to filtering and stay with the content as long as Originally purposely degraded.
Digital watermarks don’t leave a noticeable mark on the content and don’t affect it’s appearance. These are imperceptible and can be detected only by proper authorities. Digital watermarks are difficult to remove without noticeably degrading the content and are a covert means in situations where cryptography fails to provide robustness.
The content is watermarked by converting copyright information into random digital noise using a special algorithm that is perceptible only to the content creator. Digital watermarks can be read only by using the appropriate reading software. These are resistant to filtering and stay with the content as long as Originally purposely degraded.

to get information about the topic watermarking digital audio full report,ppt and related topic refer the page link bellow

http://studentbank.in/report-watermarkin...ull-report

http://studentbank.in/report-digital-audio-watermarking

http://studentbank.in/report-digital-wat...ull-report

http://studentbank.in/report-digital-watermarking--5450

http://studentbank.in/report-digital-ima...ing--28461

http://studentbank.in/report-content-dep...ech-signal

http://studentbank.in/report-digital-vid...ng-project

to get information about the topic uses of watermarking full report ,ppt and related topic refer the page link bellow

http://studentbank.in/report-digital-watermarking--5450

http://studentbank.in/report-watermarkin...ues?page=2

http://studentbank.in/report-watermarkin...evaluation

http://studentbank.in/report-watermarkin...ull-report

http://studentbank.in/report-watermarking-algorithm

http://studentbank.in/report-digital-wat...ad?page=15

http://studentbank.in/report-digital-wat...?pid=20966

http://studentbank.in/report-content-dep...ech-signal

to get information about the topic digital watermarking full report ppt and related topic refer the page link bellow

http://studentbank.in/report-digital-wat...t-download

http://studentbank.in/report-digital-watermarking--5450

http://studentbank.in/report-digital-water-marking

http://studentbank.in/report-digital-vid...ng-project

http://studentbank.in/report-watermarkin...ull-report

http://studentbank.in/report-digital-wat...ull-report

http://studentbank.in/report-digital-wat...plications

http://studentbank.in/report-digital-image-watermarking

http://studentbank.in/report-digital-wat...ad?page=15

http://studentbank.in/report-digital-wat...ad?page=22

http://studentbank.in/report-digital-wat...oad?page=4

http://studentbank.in/report-digital-wat...ad?page=17

http://studentbank.in/report-digital-wat...ad?page=19

http://studentbank.in/report-digital-wat...ad?page=18