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The illegal distribution of a digital movie is a common and significant threat to the film industry. With the advent of high-speed broadband Internet access, a pirated copy of a digital video can now be easily distributed to a global audience. A possible means of limiting this type of digital theft is digital video watermarking whereby additional information, called a watermark, is embedded in the host video. This watermark can be extracted at the decoder and used to determine whether the video content is watermarked. This paper presents a review of the digital video watermarking techniques in which their applications, challenges, and important properties are discussed, and categorizes them based on the domain in which they embed the watermark. It then provides an overview of a few emerging innovative solutions using watermarks. Protecting a 3D video by watermarking is an emerging area of research. The relevant 3D video watermarking techniques in the literature are classified based on the image-based representations of a 3D video in stereoscopic, depth-image-based rendering, and multi-view video watermarking. We discuss each technique, and then present a survey of the literature. Finally, we provide a summary of this paper and propose some future research directions.

Many illegal copies of original digital videos are being made, as they can be replicated perfectly through the Internet. Thus, it is extremely necessary to protect the copyrights of the owner and prevent illegal copying. This paper presents a novel approach to digital video watermarking for copyright protection using two different algorithms, whereby successive estimation of a statistical measure was used to detect scene boundaries and watermark was embedded in the detected scenes with discrete wavelet transform. Haar wavelet was used for decomposition. For embedding, the approaches used were (i) the detailed subband (LH subband) and (ii) the approximate subband (LL subband) of the cover video. Imperceptibility, robustness, and channel capacity were measured using both algorithms. The system was tested for robustness in the presence of 15 different attacks of five different categories, and, under multiple attacks, ensured that a wide spectrum of attack analysis has been done. The performance metrics measured included mean square error, peak signal-to-noise ratio, structural similarity index, normalized correlation, and bit error rate. The experimental results demonstrated the better visual imperceptibility and improved performance in terms of normalized correlation and bit error rate with embedding using the LL subband. Comparative analysis with existing schemes proved the improved robustness, better imperceptibility, and reduced computational time of both the proposed schemes.

In this paper, an algorithm for multiple digital watermarking based on discrete wavelet transform (DWT), discrete cosine transform (DCT), and singular value decomposition (SVD) was proposed for healthcare applications such as tele-ophthalmology, tele-medicine, tele-diagnosis, and tele-consultancy services. Multiple watermarks were used in this algorithm to reduce the consequences of medical identity thefts. In the embedding process, the cover medical image was decomposed into third-level DWT. Low-frequency bands (LH2 and LL3) were transformed by DCT, and then SVD was applied to DCT coefficients. Two watermarks in the form of images were also transformed by DCT and then SVD. The singular values of the watermark information were embedded in the singular value of the cover medical image. Watermarks were extracted using an extraction algorithm. In order to enhance the robustness performance of the image watermarks, back-propagation neural network was applied to the extracted watermarks to reduce the effects of different noise applied on the watermarked image. Results were obtained by varying the gain factor and the different cover image modalities. Experimental results were provided to illustrate that the proposed method is able to withstand a variety of signal processing attacks, and has been found to give excellent performance in terms of robustness and imperceptibility. The performance of the method was also compared with other reported techniques. Further, the visual quality of the proposed method was also evaluated by a subjective method.

In this paper a novel image based data security and authentication based, image watermarking scheme that combines the discrete wavelet transform (DWT) and Singular value decomposition (SVD) is prop...

The existing works of software watermarking have the intrinsic defects: watermarking is independent of program semantics and have weak strength and resilience to state-of-the-art reverse engineering such as symbolic execution, dynamic taint analysis and theorem proving. In this paper, we propose a semantic-integrated watermarking with tamper-proofing to mitigate such problems. This work chooses neural network as the “integrator” and skillfully integrates the watermarking and tamper-proofing module into program semantics. The difficult of reverse engineering or tampering with watermarked program is equal to extracting the rules from neural networks, which had be proven as a NP-hard problem. We have deployed our work in SPECint-2006 benchmarks to evaluate the overhead, strength and resilience. Experiment results show that our watermarking could effectively resist the state-of-the-art reverse engineering, and the introduced overhead is acceptable.

This survey presents a brief discussion of different aspects of digital image watermarking. Included in the present discussion are these general concepts: major characteristics of digital watermark, novel and recent applications of watermarking, different kinds of watermarking techniques and common watermark embedding and extraction process. In addition, recent state-of-art watermarking techniques, potential issues and available solutions are discussed in brief. Further, the performance summary of the various state-of-art watermarking techniques is presented in tabular format. This survey contribution will be useful for the researchers to implement efficient watermarking techniques for secure e-governance applications.

Digital watermarking is one of the techniques that can be used to support digital copyright protection. It enables copyright owners to insert a perceptually invisible watermark within any copy of content that is distributed on the Internet. The main aim is to use watermarks to implement copyright identification and content tracking. However, digital watermarking is not sufficient to ensure an adequate copyright protection, if it is not employed in conjunction with watermarking protocols, which define the schemes of the web transactions by which buyers can purchase protected digital content distributed by content providers in a secure manner. Therefore, watermarking protocols play a central role in the field of digital copyright protection by means of watermarking techniques. They have to ensure both a correct content protection and an easy participation of buyers in the purchase transactions of the contents distributed on the Internet. This paper presents a new watermarking protocol based on an innovative, buyer centric, and mediated design approach. The result is a secure protocol that enables buyers to easily participate in the transactions by which they can buy digital protected content, and this makes the protocol suited for the current web context.

Copyright protection and information security are two most considered issues of digital data following the development of internet and computer network. As an important solution for protection, watermarking technology has become one of the challenged roles in industry and academic research. The watermarking technology can be classified by two categories: visible watermarking and invisible watermarking. With invisible technique, there is an advantage on user interaction because of the visibility. By applying watermarking for communication, it will be a challenge and a new direction for communication technology. In this paper we will propose one new research on communication technology using optical camera communications (OCC) based invisible watermarking. Beside the analysis on performance of proposed system, we also suggest the frame structure of PHY and MAC layer for IEEE 802.15.7r1 specification which is a revision of visible light communication (VLC) standardization.

This paper presents a survey of fragile watermarking schemes for image authentication proposed in the past decade. The limited embedding capacity and extent of tampering are some of the important issues among other issues that drive the research in this area. Therefore we have presented in this survey the gist of the fragile watermarking schemes in just enough detail so that the reader may gain a fair idea of the issues, techniques adopted in general to address them and the comparison of results. The general frame work of the fragile watermarking system, different categories of attacks and parameters used to evaluate the schemes are presented in this survey. The comparative analysis and the quantitative comparison of basic schemes and their variations with improvements will help the researchers in quick review of the recent developments in this area.

The recent progress in the digital multimedia technologies has offered many facilities in the transmission, reproduction and manipulation of data. However, this advance has brought the problem such as copyright protection for content providers. Watermarking is one of the proposed solutions for copyright protection of multimedia. Most of the content provider use Photoshop to create a watermark photo, but Photoshop involve many procedures to complete a watermarked image. In addition, watermark image using Photoshop easily destroy by attacker where attacker can modifies the image to remove the watermark from the image. Hence, it has become a tough task to protect copyright of an individual’s creation. Thus, i-Mark is developed to solve the problem to protect the watermarked image. An invisible watermark embeds an imperceptible signal into data such as image, which indicates whether or not the content is copyrighted. By using i-Mark, invisible watermarking was provided where steganography method was implemented for users to encrypt message into an image. Hence, the image is protected from been easily modifies or copy by others. Meanwhile, i-Mark allow user to store their invisible watermarked image in database and can be view later. In addition, i-Mark also can made a visible watermark where user can adding text on the cover of image more convenient than Photoshop. In conclusion, i-Mark provides users to watermark their image either visible watermark or invisible watermark. Hence, throughout the project, user may use the system user friendly compare to Photoshop.

With the ease of availability and accessibility of the internet and image processing software, it has become difficult to distinguish between the original and manipulated images. To restore this lost trust in digital images, digital image watermarking is widely used. Some owner’s information is embedded within the digital image which is not only required to be robust against the various image processing operations but is required to be extracted when required and verify for the ownership of the information. One of the major issues addressed for image watermarking techniques is false watermark extraction. But overwriting the already watermarked images, that is, rewatermarking needs to be addressed. This paper analyzes three existing solutions to tackle false watermark extraction and rewatermarking.

The digital watermarking is a process of hiding an information in multimedia for copyright protection. Where, one data is hidden inside another data. We implement the watermarking algorithm in frequency domain by using a combination of DWT (Discrete Wavelet Transform) and SVD (Singular Value Decomposition) with DCT (Discrete Cosine Transform) algorithms. In which the performance analysis of an invisible watermarking can be measured with comparison of MSE (Mean Square Error) and PSNR (Peak Signal to Noise Ratio) with respect to the embedded and extracted images respectively. Here, the invisible watermarking is used to protect copyrights of multimedia contents. The invisible watermarks are the technologies which could solve the problem of copyright protection. Which is required for ownership identification as well as the hidden information can also be identified.

In the digital right management value chain, digital watermarking technology plays a very important role in digital product’s security, especially on its usage tracking and copyrights infringement authentication. However, watermark procedures can only effectively support copyright protection processes if they are applied as part of an appropriate watermark protocol. In this regard, a number of watermark protocols have been proposed in the literature and have been shown to facilitate the use of digital watermarking technology as copyright protection. One example of such protocols is the anonymous buyer-seller watermarking protocol. Although there are a number of protocols that have been proposed in the literature and provide suitable solutions, they are mainly designed as a watermarking protocol for the first-hand market and are unsuitable for second-hand transactions. As the complexity of online transaction increases, so does the size of the digital second-hand market. In this paper, we present a new buyer-seller watermark protocol that addresses the needs of customer’s rights problem in the digital secondary market. The proposed protocol consists of five sub-protocols that cover the registration process, watermarking process for the first, second and third-hand transactions as well as the identification & arbitration processes. This paper provides analysis that compares the proposed protocols with existing state-of-the-arts and shows that it has met not only all the buyer’s and seller’s requirements in the traditional sense but also accommodates the same requirements in the secondary market.

With the widespread internet usage, digital contents are easily distributed throughout the world. To eliminate concerns of producers and owners of digital contents, watermarking techniques are extensively being used. Robustness against intentional and unintentional attacks is a major quality of watermarking systems. Since different attacks tend to target different parts of the frequency spectrum, in this paper we propose a framework for blind watermarking which determines the type of attack that the image has gone through before extracting the watermark. Within this framework, we propose an attack classification method to identify the region of the frequency spectrum that is less damaged. The watermark which is redundantly spread throughout the spectrum can be extracted from the less damaged regions. Experimental results show functionality of the framework by producing better results in comparison with well-known blind watermarking techniques.

Advancements in computing and networking technologies have opened gateways for the content owners to produce and distribute their digital contents (e.g., audio/video/images) in a convenient and affordable manner. Despite all the advantages promised by the advancement in digital technology and widespread use of Internet, piracy of content is still big concern. Digital content can be easily copied without any quality loss. Content creators and owners are concerned about the consequences of illegal copying and distribution on a massive scale like loss of capital. As digital data can be duplicated and edited with great ease, this has led to Digital Rights Management (DRM) systems that can address the issues related to privacy and security of the digital contents. Digital watermarking is a promising technology employed by various DRM systems to achieve rights management. Buyer-Seller Watermarking (BSW) protocol integrates encryption, with digital watermarking and other techniques to ensure rights protection & security for seller as well as the buyer of the digital content. BSW protocols support copyright protection, piracy tracing, and privacy protection. Various approaches have been proposed for BSW protocols. In this context, the main contributions of this paper to the literature on BSW protocols are threefold: (i) it identifies the challenges in designing a BSW protocol; (ii) provides the taxonomy of existing approaches; and (iii) describes the strengths and weaknesses of the presented approaches by comparison and some open issues are highlighted. We provide a taxonomy of the existing approaches for BSW protocols.Security and performance requirements are identified.Comparative analysis of BSW protocols in terms of security and performance requirements.Identified future trends and open issues in the BSW protocols.

the digital data is transferred over the internet which may harm the digital data like tampering of data etc. Therefore, the need of digital data protection has been increased with the advancement in the technology. Watermarking is a technique used to protect the digital data. Digital watermarking is a technique by using which user can get the copyright of its product which prevents the data from tampering. Many techniques are available for video watermarking like Discrete Wavelet Transform, Least Significant Bit Technique etc. (2).The properties of digital watermarking are For copy control, In fingerprinting, For identification of ownership, For Authentication, Monitoring of digital video broadcast, In video tagging etc. (1).

Digital watermarking has been proposed as a viable clarification to the necessity of copyright protection and authentication of multimedia system information in a networked environment, since it makes possible to identify the author, owner, distributor or approved client of a document. This paper elaborates quality of discrete cosine transform for image watermarking, DCT based image watermarking technique, classification and analysis of discrete cosine transform primarily based watermarking techniques. Discrete cosine transform and wavelet based mostly image watermarking ways that. It'll be useful for researchers to implement effective image watermarking methodology .the propose algorithmic program to supply information privacy and additional authentication. Watermark embedding into host image. Propose algorithmic program also have good performance in hardiness, reliable and computing complexity. Keywords-Watermarking, Visibility, Security, Robustness, Discrete cosine transform, Reversible data hiding.

In recent years, there is a rapid growth in information technology and multimedia. At the same time information security and copyright has become an issue as piracy and malice manipulation is common. Watermarking is commonly used technique to solve the above mentioned issue. By inserting a watermark in the host audio signal the copyright problem can be solved. As a result the biggest debate in the current era is digital audio watermarking. More affordable the watermarking should be to make the extraction easier. This paper mainly discusses on audio watermarking principle, features of watermarking, performance evaluation techniques and research gap on audio watermarking.

Watermarking protocols are designed for tracing illegal distributors when unauthorized copies are found. So far, most of the proposed schemes set up two or more watermarks embedded to a copy by the seller before it was sold. The main potential concerns of multiple watermarking are the image quality would be damaged and any earlier embedded watermarks would be destroyed as well. Thanks to visual cryptography which encodes the secret image into two shares, and recovers the secret by collecting these two shares. Therefore, a new buyer-seller watermarking protocol is proposed in this paper by applying the technique of visual cryptography to Lei et al.'s scheme so as to free from the disadvantages of multiple-watermarking insertion.

Watermarking protocols are used in conjunction with digital watermarking techniques to protect digital copyright on the Internet. They define the schemes of the web transactions by which buyers can purchase protected digital content distributed by content providers in a secure manner. Over the last few years, significant examples of watermarking protocols have been proposed in literature. However, a detailed examination of such protocols has revealed a number of problems that have to be addressed in order to make them suited for current web context. Therefore, based on the most relevant problems derived from literature, this article identifies the main challenges posed by the development of watermarking protocols for web context and presents a watermarking protocol that follows a new secure, buyer-centric and mediated design approach able to meet such challenges.

Multimedia security is extremely significant concern for the internet technology because of the ease of the duplication, distribution and manipulation of the multimedia data. The digital watermarking is a field of information hiding which hide the crucial information in the original data for protection illegal duplication and distribution of multimedia data. The image watermarking techniques may divide on the basis of domain like spatial domain or transform domain or on the basis of wavelets. The spatial domain techniques directly work on the pixels and the frequency domain works on the transform coefficients of the image. This paper presents classification of watermarking, stages in watermarking, watermarking approaches and its applications.

The frequent availability of digital data such as audio, images and videos became possible to the public through the expansion of the internet. Digital watermarking technology is being adopted to ensure and facilitate data authentication, security and copyright protection of digital media. It is considered as the most important technology in today's world, to prevent illegal copying of data. Digital watermarking can be applied to audio, video, text or images. This paper includes the detail study of watermarking definition and various watermarking applications and techniques used to enhance data security.

protection of digital media is the very first application that comes to mind for digital watermarking. In the past, duplicating artwork was quite complicated and requires great efforts to create the work looks just like the original. However, in present digital world it is very simple for anyone to duplicate or manipulate digital data. The digital image watermarking allows the watermark to be embedded visibly or invisibly in the original image for identification of the owner. This concept can also be used for other media, such as digital video and audio. Telemedicine is a well-known application of digital watermarking. In this application security & authentication for medical data is very important. Hiding the data into the medical image provide the security over the public network. Authentication verifies whether the image certainly belongs to the right patient Authentication of medical data used for further diagnosis and reference. This paper focused on the methods of medical image data hiding for security and authentication. High capacity data hiding is achieved with CDCS (Class Dependent Coding Scheme). As well as data is effectively hided with discrete wavelet transform. Embedding watermarks in RONI (region of non interest) protects the ROI (region of interest) of medical image, which is diagnostically important part of medical images. Segmentation plays an important role in medical image processing for separating the ROI from medical image.

Data protection from malicious attacks and misuse has become a crucial issue. Various types of data, including images, videos, audio and text documents, have given cause for the development of different methods for their protection. Cryptography, digital signatures and steganography are the most well known technologies used to protect data. During the last decade, digital watermarking technology has also been utilized as an alternative to prevent media forgery and tampering or falsification to ensure both copyright and authentication. Much work has been done to protect images, videos and audio but only a few algorithms have been considered for text document protection with digital watermarking. However, our survey observed that available text watermarking algorithms are neither robust nor imperceptible and as such remain unsecured methods of protection. Hence, research to improve the performance of text watermarking algorithms is required. This paper reviews current watermarking algorithms for text documents and categorizes text watermarking methods based on the way the text was treated during the watermarking process. It also discusses merits and demerits of available methods as well as recent proposed methods for evaluating text watermarking systems and the need for further research on digital text watermarking.

Over the last 25 years, there has been much work on multimedia digital watermarking. In this domain, the primary limitation to watermark strength has been in its visibility. For multimedia watermarks, invisibility is defined in human terms (that is, in terms of human sensory limitations). In this paper, we review recent developments in the non-media applications of data watermarking, which have emerged over the last decade as an exciting new sub-domain. Since by definition, the intended receiver should be able to detect the watermark, we have to redefine invisibility in an acceptable way that is often application-specific and thus cannot be easily generalized. In particular, this is true when the data is not intended to be directly consumed by humans. For example, a loose definition of robustness might be in terms of the resilience of a watermark against normal host data operations, and of invisibility as resilience of the data interpretation against change introduced by the watermark. In this paper, we classify the data in terms of data mining rules on complex types of data such as time-series, symbolic sequences, data streams, and so forth. We emphasize the challenges involved in non-media watermarking in terms of common watermarking properties, including invisibility, capacity, robustness, and security. With the aid of a few examples of watermarking applications, we demonstrate these distinctions and we look at the latest research in this regard to make our argument clear and more meaningful. As the last aim, we look at the new challenges of digital watermarking that have arisen with the evolution of big data.

Multimedia contents such as images, videos, audio, and texts are easy to available for download through internet in worldwide. Duplication of multimedia contents is to create using different software. This type of operation some time created problem of copyright and ownership authentication. Digital watermarking techniques are usedto protect multimedia contents. This paper gives various watermarking techniques in transform domain and sparse domain for protection and authentication of multimedia contents.

The rapid development of the Internet and digital image modification software has invited the illegal access to and use of digital images. In response, digital watermarking has emerged as a unique tool for protecting the authenticity of digital images. This technique involves the insertion of an imperceptible message within the media. This paper proposes a semi-fragile watermarking system using content-based techniques that address the challenge of image authentication. The proposed algorithm exploits the Zernike moments to authenticate an image and the Sobel edge map to perform tamper detection. The main contributions of this work are the establishment of an authentication algorithm that is robust against scaling, translation, noise pollution, rotation and JPEG compression, which are considered to be non-malicious modifications, while significantly decreasing the computational complexity using optimum orders of Zernike moments. In addition, this work addresses the challenge of capacity in terms of watermark insertion while preserving the visual quality of the image, where the capacity is increased almost three fold, as shown in the results. This process can successfully distinguish malicious attacks and reject modifications to watermarked images made through additions, replacements, and image cropping.

A digital watermark is a type of indicator covertly embedded in the noise tolerant signal such as an image or audio data. Digital watermarking is the method that embeds information known as a watermark into the multimedia object such that the watermark can be extracted or detected later to create an assertion about the object. Embedded watermark will permit recognizing the owner of the work hardware implementation. This idea is applicable for the digital video and audio also. Embedding a digital signal (image, video or video) with data which cannot be easily eliminated is called digital watermarking. Digital watermarks may be used to the authenticate the integrity or authenticity of the carrier signal or to display the identity of its owners Digital watermarking is used as a key result to create the document transferring protected from unlawful interferences. Digital watermark methods are used in numerous areas such as copyright owner identification, protection and broadcast monitoring. Digital watermarking is the processing of combined information into a digital signal. A watermark is a secondary image, which is overlaid on the host image, and provides a means of protecting the image. In this paper, aim is to present a survey of numerous methods on the basis of digital image watermarking. The digital watermarking method is becoming more important in this developing society of internet. The goal of this implementation is to survey the different techniques for Digital Watermarking.

digital word it is very common to distribute digital image as a part of multimedia technology by use of the Internet. Security of this digital data over the Internet is very popular field among researchers. Watermarking is a process that embeds data or watermark inside data such that it cannot be easily accessed by authorized person. Watermarking provides copyright protection of digital data. Digital Image Water marking is a subfield of Digital watermarking, and it concerns with protection of digital image from unauthorized reproduction and modification. In digital watermarking, a secondary image is a watermark and this watermark lied into the host image and provides protection. Different Digital Image watermarking methods have been proposed in this field to maintain content authentication, copyright protection, tamper protection and many other application. This paper presents a model for digital image watermarking, properties and applications. Moreover, this paper present a survey on different types of digital Image watermarks. This paper reviews different aspects of digital image watermarking for protecting digital data and provide review of digital image watermarking methods named: Least Significant Bit (LSB), Discrete Wavelet Transform (DWT), Discrete Cosine Transform (DCT), and Singular Value Decomposition (SVD).

We presented in this survey, digital watermarking is an important method to add hidden patent notices to digital audio, image. The Watermarking techniques with frequency domain make better results either concern with image excellence or invisibility of the watermark. In this paper, we present review on Image Watermarking for Good Robustness. In this paper, we talk about the various factors used in watermarking, properties and application area where water- marking technique requires to be used. Also a survey on the some new work is done in image watermarking field.

with the extensive use of internet all over the world, most of the government, public and private data are increasingly being published on internet. The protection of these online documents is the need of the hour and need to be dealt with urgently. Text watermarking is the technique which helps to protect the authenticity and integrity of text documents by inserting watermarks in the text. Text watermarking is an active area of research from several years. This paper presents a review of various text watermarking techniques described in literature. We also highlight the security issues like copyright protection, tamper detection and data hiding which need to be focussed for ensuring text security. Keywordswatermarking, Copyright Protection, Security, Encryption, Tampering.

Now days due to advancement of technology & high speed internet, the access and transfer of digital media such as image, text, audio and video becomes easy for everybody. Because of the increased use of internet, the need of security and authenticity has become essential. To secure the multimedia data, digital watermarking techniques have become key tool to tackle the challenges faced by the rapid distribution of digital content over the internet. Digital watermarking is a branch of information hiding which is used to hide proprietary information in digital media like photographs, digital music, digital video etc. In this paper we have developed image watermarking model based on discrete wavelet transform. In this technique, we embed and extract biometric watermark using the alpha blending technique in low frequency band. This paper illustrates a general architecture and modified algorithm for DWT based digital watermarking. To demonstrate working of the aforementioned architecture and algorithm, an experimental system is also developed with different value of alpha at 1,2 and 3 level of DWT. This paper also describes output of the experimental system with their comparison.

Digital Watermarking is a technology used for the copyright protection of digital applications. Watermarking is a concept of embedding a special symbol, watermark, into an electronic document so that a given piece of copyright information is permanently tied to the data. It is an effective way to protect copyright of multimedia data even after its transmission. In recent years image watermarking techniques are grown-up. So digital video watermarking is the next challenging task and it is becoming a current academic research topic. Digital watermarking is a process of embedding watermark into digital document, where watermark can be some binary data, a small image or a seed value. It can also be any arbitrary or serial number, possession identifier, information about the inventor, date etc, that would be inserted into the original digital products. Digital watermarking refers to embedding watermarks in a multimedia documents and files in order to protect them from illegal copying and identifying manipulations. We proposed a technique is Hybrid DWT, PCA and SVD method for digital video watermarking. In two parts a proposed method of watermarking is divided: watermark embedding and watermark extracting.

Due to the problem that the many digital images can be modified more and more easily, watermarking algorithms are proposed. There are many types of digital watermarking algorithms, such as robust digital watermarking algorithms, watermarking schemes for authentication, and reversible digital watermarking algorithms. However, there are some special images, such as the digital medical images for remote treatment, the military images for tracking object, and the remote sensing images, and they are so sensitive to any modification that we should authenticate the copyright by special technique. And this technique is zero-bit watermarking algorithms. In this paper, about zero-bit watermarking algorithms are surveyed. The basic procedures of these classical algorithms are analyzed, and some suggestion about the zero-bit algorithms is given.

Over the past few years, reversible watermarking techniques for relational databases have been proposed to provide protection of ownership rights, data tempering, and data integrity. Mainly, these techniques ensure original data recovery from watermarked data, whereas irreversible watermarking schemes only protect ownership rights. This characteristic of reversible watermarking has emerged as a candidate solution for the protection of ownership rights of data, intolerable to modifications such as medical data, genetic data, credit card, and bank account data. The main objective of this paper is to make an extensive survey of the state-of-the-art in reversible watermarking techniques for relational databases to reflect recent research progress and to point out the key issues for future research. In order to analyze these techniques, a classification has been performed on the basis of i the extent of modifications introduced by the watermarking scheme in the underlying data and ii the robustness of the embedded watermark against malicious attacks. Copyright © 2015 John Wiley & Sons, Ltd.