Software Watermarking Dinamis dengan Algoritme Collberg-Thomborson Dan Parent Pointer Graf pada Aplikasi Android

<p class="15"><em>Smartphone</em> merupakan alat umum yang digunakan masyarakat dalam kehidupan sehari-hari. Sistem operasi yang paling banyak digunakan pada smartphone adalah Android. Aplikasi pada Android dapat diperoleh tidak hanya di Play Store saja, namun juga dapat ditemukan secara bebas di <em>website-website</em> yang berada di internet. Oleh karena itu aplikasi Android rentan terhadap pembajakan.<em> Software watermarking</em> merupakan metode umum yang biasanya digunakan untuk mengantisipasi pembajakan perangkat lunak dengan menyisipkan informasi pengenal ke dalam suatu program. Tujuan dari <em>software watermarking</em> adalah untuk membuktikan kepemilikan dari sebuah program. Salah satu teknik watermarking adalah <em>dynamic watermarking. </em>Teknik ini akan men-<em>generate</em> <em>watermark</em> ketika program dieksekusi. <em>Dynamic Graph Watermarking</em> (DGW) merupakan salah satu metode dalam <em>software watermarking</em>. Dalam penyisipan <em>watermark, </em>metode ini menggunakan struktur graf yang dibuat berdasarkan enumerasi graf. Salah satu algoritma dalam DGW adalah Colberg-Thomborson (CT) <em>algorithm. </em>Algoritma tersebut menggunakan <em>code</em> yang dapat membentuk <em>watermark </em>saat <em>runtime program</em><em>.</em> Pemberian <em>watermark</em> terhadap sebuah aplikasi dilakukan dengan menggunakan CT <em>algorithm</em> dan enumerasi <em>Parent Pointer Graph (PPG).</em> Untuk menyisipkan watermark terhadap aplikasi Android, dibuat sebuah <em>library</em> Java dan sebuah simulator berbasis desktop untuk mengekstrak <em>watermark</em>. Dari hasil pengujian dapat disimpulkan bahwa PPG dapat digunakan sebagai enumerasi pada metode DGW dan memiliki tingkat ketahanan yang tinggi terhadap <em>distortive</em><em> attack </em>namun tidak pada <em>subtractive </em>dan<em> additive attack</em>. Dari penelitian juga diperoleh hasil bahwa pemberian <em>watermark</em> memberikan penambahan <em>size</em> pada apk Android namun tidak mempengaruhi peningkatan penggunaan <em>memory</em> dan <em>processor</em> aplikasi.</p><p class="15"> </p><p class="15"><em><strong>Abstract </strong></em></p><p class="15"><em>Smartphones are common tools in people’s daily life. The most common operating in smartphone is Android. Our android application can be obtained not only in the Play Store, but also free websites on the internet. Therefore, Android applications are vulnerable to piracy. Software watermarking is a common method used to anticipate software piracy by inserting identifying information into a program. The purpose of software watermarking is to prove ownership of a program. One of the watermarking techniques is dynamic watermarking that generates watermarks when the program is executed. Dynamic Graph Watermarking (DGW) is one of the software watermarking methods. This method uses a graph structure which created based on graph enumeration in inserting the watermark. One of the DGW algorithm is Colberg-Thomborson (CT) which use code that can form a watermark at program run time. For watermarking an application, we use CT algorithm and Parent Pointer Graph (PPG) enumeration. To embed watermark to the android application we create a Java library and a desktop-based simulator to extract watermark from android application. Our result shows that PPG can be used as an enumeration and has robustness in defending against distortive attack but not to subtractive and additive attacks. we also get that watermark gives an additional size to an android apk but it does not affect the increase in memory and processor usage.</em></p><p align="justify"> </p>

An Optimized Digital Watermarking Scheme Based on Invariant DC Coefficients in Spatial Domain

Digital watermarking has become an essential and important tool for copyright protection, authentication, and security of multimedia contents. It is the process of embedding a watermark in the multimedia content and its extraction. Block-based discrete cosine transform (DCT) is a widely used method in digital watermarking. This paper proposes a novel blind image watermarking scheme developed in the spatial domain by quantization of invariant direct current (DC) coefficients. The cover image is redistributed and divided into non-overlapped square blocks and then the DC coefficients invariant to rotation, row and column flip operations, without utilization of the DCT transform, are directly calculated in the spatial domain. Utilizing the quantization parameter and watermark information, the modified DC coefficients and the difference between DC and modified DC coefficients are calculated to directly modify the pixel values to embed watermark bits in the spatial domain instead of the DCT domain. Optimal values of the quantization parameter, which plays a significant role in controlling the tradeoff between robustness and invisibility, are calculated through differential evolution (DE), the optimization algorithm. Experimental results, compared with the latest similar schemes, demonstrate the advantages of the proposed scheme.

Border following–based reversible watermarking algorithm for images with resistance to histogram overflowing

Histogram shifting is an effective manner to achieve reversible watermarking, which works by shifting pixels between the peak point and its nearest zero point in histogram to make room for watermark embedding. However, once zero point is absent, the algorithm suffers from overflowing problem. Even though some works attempt to deal with this risk by introducing auxiliary information, such as a location map, they occupy a lot of embedding capacity inevitably. In this article, in order to deal with overflowing problem efficiently, we propose a border following–based reversible watermarking algorithm for images. With the help of border following algorithm and pre-processing, available regions with at least one zero point are recognized to embed watermark so that auxiliary information is not needed any more. And the algorithm utilized also ensures the same border can be re-recognized from the watermarked image without error, thus the correctness is also guaranteed. The performance of the proposed algorithm is evaluated using classic image datasets in this area, and the results not only validate the effectiveness of the proposed algorithm but also indicate its advantages compared with the classic histogram shifting–based reversible watermarking algorithm as well as the state of the art.

Homomorphic Encryption-Based Robust Reversible Watermarking for 3D Model

Robust reversible watermarking in an encrypted domain is a technique that preserves privacy and protects copyright for multimedia transmission in the cloud. In general, most models of buildings and medical organs are constructed by three-dimensional (3D) models. A 3D model shared through the internet can be easily modified by an unauthorized user, and in order to protect the security of 3D models, a robust reversible 3D models watermarking method based on homomorphic encryption is necessary. In the proposed method, a 3D model is divided into non-overlapping patches, and the vertex in each patch is encrypted by using the Paillier cryptosystem. On the cloud side, in order to utilize addition and multiplication homomorphism of the Paillier cryptosystem, three direction values of each patch are computed for constructing the corresponding histogram, which is shifted to embed watermark. For obtaining watermarking robustness, the robust interval is designed in the process of histogram shifting. The watermark can be extracted from the symmetrical direction histogram, and the original encrypted model can be restored by histogram shifting. Moreover, the process of watermark embedding and extraction are symmetric. Experimental results show that compared with the existing watermarking methods in encrypted 3D models, the quality of the decrypted model is improved. Moreover, the proposed method is robust to common attacks, such as translation, scaling, and Gaussian noise.

A High Capacity Watermarking Technique for the Printed Document

Digital watermarking technology is an effective method for copyright protection of digital information, such as images, documents, etc. In this paper, we propose a high capacity text image watermarking technique against printing and scanning processes. Firstly, this method obtains the invariant in the process of printing and scanning under the mathematical hypothesis model of print-scan transformation. Then based on the print-scan invariant, the Fourier descriptor is used to flip the trivial pixel points with high frequency information on the character boundary. Next, considering the resolution of the print-scan equipment and its influence on the print-scan invariant, a quadratic quantization function is proposed to embed watermark information of multiple bits for a single character. Finally, the QR code (Quick Response code) is researched, which has large information capacity, robust error correction ability and high decoding reliability. By using the QR code as the watermark information, we can reduce the impact of bit error rate during watermark extraction, and the robustness of the watermark information can be improved. The experimental results show that the proposed text watermarking algorithm has the advantages of anti-print scanning, anti-scaling, large capacity and good visual effects.

A Secure and Robust Digital Image Watermarking Techniques

This paper speaks to various Digital Watermarking systems which allows a person to include unseen copyright see just as some other confirmation messages to pictures with the goal that it very well may be shielded from the unapproved get to. The principle point of paper is to investigate the examination of different digital picture watermarking schemes and it likewise exhibits that all these watermarking strategies gives picture watermarking full protection and sensible limit. Here hybrid Image watermarking procedure which takes the benefits of various transforms like DWT, DCT, SVD and Arnold Transform, which improves greater security and gives heartiness to the watermark. In this paper technique, picture is separated into a few gatherings of edges, and one of the casings is chosen where watermark will be implanted. Before embed watermark in a choose casing it will be pre-handled with Arnold Transform which will give security to it.

Effect of different attacks on image watermarking using dual tree complex wavelet transform (DTCWT) and principle component analysis (PCA)

Perceptibility and robustness are two incongruous requirements demanded by digital image watermarking for digital right management and other applications. A realistic way to concurrently satisfy the two contradictory requirements is to use robust watermark algorithm. The developed algorithm uses DTCWT and PCA techniques to embed watermark signal in host signal. To prove the algorithm robustness without much affecting perceptibility several attacks like noises, cropping, blurring, rotation are applied and tested by varying attack parameters. Parameters like Peak signal noise ratio and Correlation Coefficient are calculated for each attack. Attack percentage is varied and performance parameters are calculated to prove the robustness of the developed algorithm.

A New Reversible Database Watermarking Approach with Firefly Optimization Algorithm

Up-to-date information is crucial in many fields such as medicine, science, and stock market, where data should be distributed to clients from a centralized database. Shared databases are usually stored in data centers where they are distributed over insecure public access network, the Internet. Sharing may result in a number of problems such as unauthorized copies, alteration of data, and distribution to unauthorized people for reuse. Researchers proposed using watermarking to prevent problems and claim digital rights. Many methods are proposed recently to watermark databases to protect digital rights of owners. Particularly, optimization based watermarking techniques draw attention, which results in lower distortion and improved watermark capacity. Difference expansion watermarking (DEW) with Firefly Algorithm (FFA), a bioinspired optimization technique, is proposed to embed watermark into relational databases in this work. Best attribute values to yield lower distortion and increased watermark capacity are selected efficiently by the FFA. Experimental results indicate that FFA has reduced complexity and results in less distortion and improved watermark capacity compared to similar works reported in the literature.

Digital Watermarking Processing Technique Based on Overcomplete Dictionary

A novel sparse domain-based information hiding framework is proposed in this paper to attach the watermarking signal to the most significant sparse components of the host signal over the pre-defined overcomplete dictionary. The adaptive sparse domain can be utilized to embed watermarking logo with better security and robustness. This can be realized owing to the fact that, not only the sparse domain can be customized from the given samples, but also the sparse transform coefficients of the original watermarking signal can be embedded, which provides inherent privacy. This paper provides two kinds of methods that embed watermark directly and embed the sparse representation coefficients of watermarking logo, and analyzes the condition of uniqueness of the sparse solution. Experimental results demonstrate the superiority of the proposed sparse domain digital watermarking technique over the traditional frequency domain or spatial domain schemes.