Yarmouk universityYarmouk universityHijjawi faculty for engineering technologyHijjawi faculty for engineering technology

Computer engineering departmentComputer engineering departmentPrimary Graduation projectPrimary Graduation project

Document security using watermarking Document security using watermarking techniquetechnique

Under the supervision of:Under the supervision of:Eng.hadeel kasaymehEng.hadeel kasaymeh

Prepared by:Prepared by:

Hussain al-afeefHussain al-afeefAbd alkareem al-rabbaeAbd alkareem al-rabbae

Saif bni-easaSaif bni-easaOsama shatnaweOsama shatnaweIsmael al-sheiabIsmael al-sheiab

outlinesoutlines

1-1- introduction about document security.. introduction about document security..

2-2- watermarking technique????? watermarking technique?????

3-3- watermarking types…. watermarking types….

4-4- practical application on the pixels in practical application on the pixels in

some image…some image…

5-5- conclusion… conclusion…

IntroductionIntroductionPowerful signal processing techniques and Powerful signal processing techniques and ease of modification have made the world ease of modification have made the world shift towards digital representation of shift towards digital representation of multimedia signals such as image, audio multimedia signals such as image, audio and video. The rapid growth of Internet is and video. The rapid growth of Internet is also fuelling this process. The vendors fear also fuelling this process. The vendors fear to put their multimedia data over the to put their multimedia data over the Internet, because there is no way to track Internet, because there is no way to track the illegal distribution and violation of the illegal distribution and violation of copyright protection. copyright protection. WatermarkingWatermarking comes comes into the scenario as a powerful solution to into the scenario as a powerful solution to this problem. this problem.

What is the DIGITAL What is the DIGITAL WATERMARKING?WATERMARKING?

Digital watermarking is the process of Digital watermarking is the process of possibly irreversibly embedding information possibly irreversibly embedding information into a digital signal. The signal may be into a digital signal. The signal may be audio, pictures or video. audio, pictures or video.

for example, If the signal is copied, then the for example, If the signal is copied, then the information is also carried in the copy. It is information is also carried in the copy. It is the process of altering the original data file. the process of altering the original data file. Depending on the specific method used, and Depending on the specific method used, and we will present it later which is called we will present it later which is called adjusted purpose watermarking technique adjusted purpose watermarking technique … …

An advantage of the digital An advantage of the digital watermarking:-watermarking:-

Is to detect the images that may contain Is to detect the images that may contain unauthorized changes and even help in unauthorized changes and even help in recovering some of the lost data.recovering some of the lost data.

A disadvantageA disadvantage of digital of digital watermarkingwatermarking:-:-

Is that a subscriber cannot significantly Is that a subscriber cannot significantly alter some files without sacrificing the alter some files without sacrificing the quality or utility of the data. This can be quality or utility of the data. This can be true of various files including image data, true of various files including image data, audio data, and computer code.audio data, and computer code.

Watermark can be divided into Watermark can be divided into tow types:tow types:

1-visible watermarking1-visible watermarking::The information is text or a logo which The information is text or a logo which identifies the owner of the media. identifies the owner of the media.

2-invisible watermarking2-invisible watermarking::Information is added as digital data to Information is added as digital data to audio, picture or video, but it cannot be audio, picture or video, but it cannot be perceived as such (although it is possible to perceived as such (although it is possible to detect the hidden information).detect the hidden information).

Adjusted purpose (AP) for digital Adjusted purpose (AP) for digital watermarking techniquewatermarking technique

There are two categories in image There are two categories in image watermarking according to its embedding watermarking according to its embedding domains:domains:

Spatial domain:-Spatial domain:- In spatial domain, we can simply insert a In spatial domain, we can simply insert a

watermark into a host image by changing watermark into a host image by changing gray levels of some pixels in the host gray levels of some pixels in the host image.image.Advantage:Advantage:

Simple, easy and fast. Simple, easy and fast. DisadvantageDisadvantage::

The inserted information could be easily detected The inserted information could be easily detected by computer analysis.by computer analysis.

Frequency domain:-Frequency domain:-

In frequency domain, we can insert a In frequency domain, we can insert a watermark into coefficients of a transformed watermark into coefficients of a transformed image, for example:image, for example:

The Discrete Fourier Transforms The Discrete Fourier Transforms (DFT).(DFT). The Discrete Cosine Transforms The Discrete Cosine Transforms (DCT).(DCT). The Discrete Wavelet Transforms The Discrete Wavelet Transforms (DWT).(DWT).

Advantage:Advantage: The inserted information is generally The inserted information is generally difficult to be detected.difficult to be detected.Disadvantages:Disadvantages:We cannot embed large amounts of data We cannot embed large amounts of data in the frequency domain; because quality in the frequency domain; because quality of the host image will be distorted of the host image will be distorted significantly.significantly.The data embedded in coefficients of a The data embedded in coefficients of a transformed image will be somewhat transformed image will be somewhat distorted in the transformation from distorted in the transformation from frequency to spatial domain due to frequency to spatial domain due to conversion from real numbers into conversion from real numbers into integers.integers.

Watermarks can be categorized into two Watermarks can be categorized into two types According to embedding purposes:types According to embedding purposes:

1-Robust:-1-Robust:- They are usually used for copyright They are usually used for copyright

protection to declare the rightful protection to declare the rightful ownership. ownership.

2-Fragile2-Fragile:-:- For the purpose of authentication, fragile For the purpose of authentication, fragile

watermarks are adopted to detect any watermarks are adopted to detect any unauthorized modificationunauthorized modification..

We can adjust the approach of We can adjust the approach of performing watermarking from performing watermarking from spatial to frequency domain by spatial to frequency domain by adjusting the size of adjusting the size of (VSTW)(VSTW) varying sized transform windowvarying sized transform window.. Performing of watermarking will Performing of watermarking will become the spatial-domain approach become the spatial-domain approach whenwhen

VSTW = 1×1VSTW = 1×1, and the frequency-, and the frequency-domain approach for other sizes. domain approach for other sizes.

Also we can adjust the purpose of Also we can adjust the purpose of watermarking from fragile to robust watermarking from fragile to robust by adjusting the value of by adjusting the value of ((QFQF)) quantity quantity factor.factor. The embedded watermarks will The embedded watermarks will become robust if become robust if QFQF is large, and is large, and become fragile become fragile ifif QF is 1QF is 1. The . The strategies for adjusting strategies for adjusting VSTWVSTW and and QFQF are described later.are described later.

The strategies for adjusting The strategies for adjusting VSTWVSTW and and QFQF

The size of The size of VSTWVSTW can determine whether can determine whether the spatial or frequency domain is the spatial or frequency domain is adopted. For example, if the adopted. For example, if the size is 1×1size is 1×1, it , it is equivalent to the spatial-domain is equivalent to the spatial-domain approach. If the size is approach. If the size is 2×2, 4× 4, or 8 ×82×2, 4× 4, or 8 ×8, , It belongs to the frequency-domain It belongs to the frequency-domain approach. Note that, the size of approach. Note that, the size of VSTWVSTW could be arbitrary, not necessarily a could be arbitrary, not necessarily a square of power of square of power of 22. .

In principle, In principle, fragilefragile watermarks are watermarks are embedded into embedded into LSBLSB, and , and robustrobust watermarks watermarks are into are into HSBHSB. In order to integrate both . In order to integrate both watermarks, the quantity factor watermarks, the quantity factor (QF)(QF) is is developed based on the spread spectrum. developed based on the spread spectrum. We know that shifting the binary bits of x to We know that shifting the binary bits of x to leftleft (denoted as shl) or (denoted as shl) or rightright (denoted as (denoted as shr) by shr) by y y bits is equivalent to multiplying or bits is equivalent to multiplying or dividing dividing x by 2^yx by 2^y . The position for . The position for embedding the watermark can be embedding the watermark can be determined based on the determined based on the QFQF as shown in as shown in Table bellow. Table bellow. For exampleFor example, if the watermark , if the watermark is embedded into the fourth bit (i.e., QF = is embedded into the fourth bit (i.e., QF = 8) of a pixel, we will divide the pixel value 8) of a pixel, we will divide the pixel value by by 88, and then replace the resulting , and then replace the resulting LSBLSB by by the watermark. Finally, we multiply the the watermark. Finally, we multiply the result by result by 88 to obtain the watermarked to obtain the watermarked value. value.

Table:Table:The relation between QF and the embedded The relation between QF and the embedded

position of the watermarkposition of the watermark

Int. Int. Binary Binary Embedded watermark Embedded watermark Embedded position Embedded position QF QF After embeddingAfter embedding New int. New int.

41 00101001 0 1 (LSB) 1 00101000 4041 00101001 0 1 (LSB) 1 00101000 4043 00101011 0 4 8 00100011 3543 00101011 0 4 8 00100011 3566 01000010 0 2 2 01000000 6466 01000010 0 2 2 01000000 64110 01101110 0 4 8 01100110 102110 01101110 0 4 8 01100110 102210 11010010 0 5 16 11000010 194210 11010010 0 5 16 11000010 194

The watermarks should not be embedded The watermarks should not be embedded into insignificant regions of an image or its into insignificant regions of an image or its spectrum since many signal and geometric spectrum since many signal and geometric processes could affect these components.processes could affect these components.For robustness, they suggested that For robustness, they suggested that watermarks should be embedded into watermarks should be embedded into regions with large magnitudes in regions with large magnitudes in coefficients of a transformed image. If the coefficients of a transformed image. If the watermarks embedded in insignificant watermarks embedded in insignificant regions, the original image will have huge regions, the original image will have huge degradations; therefore, the size of degradations; therefore, the size of embedded watermarks is quite limited embedded watermarks is quite limited In order to enlarging the capacity of In order to enlarging the capacity of watermarks; small size of watermarks; small size of VSTWVSTW is is selected .considering robustness the selected .considering robustness the watermark is embedded into the higher watermark is embedded into the higher significant bits; therefore, by the significant bits; therefore, by the VSTWVSTW, we , we can determine the size of each sub-image to can determine the size of each sub-image to enlarge the capacity of the Watermarks.enlarge the capacity of the Watermarks.

Conclusion:-Conclusion:-Digital watermarking has been Digital watermarking has been demonstrated to be very useful in demonstrated to be very useful in identifying the source, creator, owner, identifying the source, creator, owner, distributor, or authorized consumer of a distributor, or authorized consumer of a document or an image. It can be used for document or an image. It can be used for tracking the images that were illegally tracking the images that were illegally distributed. distributed.

There are many purpose-oriented There are many purpose-oriented watermarking techniques. For example, watermarking techniques. For example, robust watermarks are used to withstand robust watermarks are used to withstand malicious attacks, fragile watermarks are malicious attacks, fragile watermarks are applied for ownership authentication.applied for ownership authentication.

Further examples are the embedding Further examples are the embedding strategies, some in spatial or frequency strategies, some in spatial or frequency domain, and some in the combination of domain, and some in the combination of both. both.

To integrate all of these, we have presented To integrate all of these, we have presented an adjusted-purpose digital watermarking an adjusted-purpose digital watermarking technique that uses two parameters, technique that uses two parameters, VSTWVSTW and and QFQF, to choose the desired one , to choose the desired one particular watermarking. Therefore, when particular watermarking. Therefore, when users design their own watermarking users design their own watermarking approaches, they can adopt our technique approaches, they can adopt our technique as a platform to make a suitable as a platform to make a suitable adjustment. adjustment.

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We want to thank our We want to thank our colleagues Good for listening colleagues Good for listening

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