We evaluated a technique for protecting the copyright of digital data for 3-D printing. To embed copyright information, the inside of a 3-D printed object is constructed from fine domains that have different physical characteristics from those of the object's main body surrounding them, and to read out the embedded information, these fine domains inside the objects are detected using nondestructive inspections such as X-ray photography or thermography. In the evaluation, copyright information embedded inside the 3-D printed object was expressed using the depth of fine cavities inside the object, and X-ray photography were used for reading them out from the object. The test sample was a cuboid 46mm wide, 42mm long, and 20mm deep. The cavities were 2mm wide and 2mm long. The difference in the depths of the cavities appeared as a difference in the luminance in the X-ray photographs, and 21 levels of depth could be detected on the basis of the difference in luminance. These results indicate that under the conditions of the experiment, each cavity expressed 4 to 5bits of information with its depth. We demonstrated that the proposed technique had the possibility of embedding a sufficient volume of information for expressing copyright information by using the depths of cavities.

A visible watermarking technique to provide copyright protection for portrait images is proposed in this paper. The proposal is focused on real-world applications where a portrait image is printed and illegitimately used for commercial purposes. It is well known that this is one of the most difficult challenges to prove ownership through current watermark techniques. We propose an original approach which avoids the deficiencies of typical watermarking methods in practical scenarios by introducing a smart process to automatically detect the most suitable region of the portrait image, where the visible watermark goes unnoticed to the naked eye of a viewer and is robust enough to remain visible when printed. The position of the watermark is determined by performing an analysis of the portrait image characteristics taking into account several conditions of their spatial information together with human visual system properties. Once the location is set, the watermark embedding process is performed adaptively by creating a contrast effect between the watermark and its background. Several experiments are performed to illustrate the proper functioning of the proposed watermark algorithm on portrait images with different characteristics, including dimensions, backgrounds, illumination and texture, with the conclusion that it can be applied in many practical situations.

This letter presents a new blind audio watermarking scheme using eigenvalue decomposition (EVD). Initially, the original audio is divided into frames and the samples of each frame are arranged into a square matrix. EVD is applied to each of these matrices. Watermark data is embedded into the largest eigenvalue of each diagonal matrix by quantization. Data embedding rate of the proposed scheme is 172.39bps. Simulation results confirm the imperceptibility of the proposed scheme and its higher robustness against various attacks compared to the state-of-the-art watermarking methods available in the literature.

This paper introduces amplitude-only images to image trading systems in which not only the copyright of images but also the privacy of consumers are protected. In the latest framework for image trading systems, an image is divided into an unrecognizable piece and a recognizable but distorted piece to simultaneously protect the privacy of a consumer and the copyright of the image. The proposed scheme uses amplitude-only images which are completely unrecognizable as the former piece, whereas the conventional schemes leave recognizable parts to the piece which degrades privacy protection performance. Moreover, the proposed scheme improves the robustness against copyright violation regardless of the used digital fingerprinting technique, because an amplitude-only image is larger than the piece in the conventional scheme. In addition, phase-only image is used as the second piece in the proposed scheme, the consumer can confirm what he/she bought. Experimental results show the effectiveness of the proposed scheme.

In this paper, 1) it is shown that amplitude-only images (AOIs) have quite wide intensity ranges (IRs), and 2) an IR reduction method for AOIs is proposed. An AOI is the inversely transformed amplitude spectra of an image, and it is used in the privacy- and copyright-protected image trading system because of its invisibility. Since an AOI is the coherent summation of cosine waves with the same phase, the IR of the AOI is too large to be stored and/or transmitted. In the proposed method, random signs are applied to discrete Fourier transformed amplitude coefficients to obtained AOIs with significantly lower IRs without distortion while keeping the invisibility of images. With reasonable processing time, high correct watermark extracting rates, inversely quantized AOIs with low mean squared errors, and reconstructed images with high peak signal-to-noise ratios are obtained by a linear quantizer in the proposed method.

Broadcast encryption scheme with personalized messages (BEPM) is a new primitive that allows a broadcaster to encrypt both a common message and individual messages. BEPM is necessary in applications where individual messages include information related to user's privacy. Recently, Fujii et al. suggested a BEPM that is extended from a public key broadcast encryption (PKBE) scheme by Boneh, Gentry, and Waters. In this paper, we point out that 1) Conditional Access System using Fujii et al.'s BEPM should be revised in a way that decryption algorithm takes as input public key as well, and 2) performance analysis of Fujii et al.'s BEPM should be done depending on whether the public key is transmitted along with ciphertext or stored into user's device. Finally, we propose a new BEPM that is transmission-efficient, while preserving O(1) user storage cost. Our construction is based on a PKBE scheme suggested by Park, Kim, Sung, and Lee, which is also considered as being one of the best PKBE schemes.

This paper presents a method for comparing and detecting clones of Java programs by analyzing program stack flows. A stack flow denotes an operational behavior of a program by describing individual instructions and stack movements for performing specific operations. We analyze stack flows by simulating the operand stack movements during execution of a Java program. Two programs for detection of clones of Java programs are compared by matching similar pairs of stack flows in the programs. Experiments were performed on the proposed method and compared with the earlier approaches of comparing Java programs, the Tamada, k-gram, and stack pattern based methods. Their performance was evaluated with real-world Java programs in several categories collected from the Internet. The experimental results show that the proposed method is more effective than earlier methods of comparing and detecting clones of Java programs.

Broadcasters transmit TV programs and often need to transmit an individual message, e.g. an individual contract, to each user. The programs have to be encrypted in order to protect the copyright and the individual messages have to be encrypted to preserve the privacy of users. For these purposes, broadcasters transmit not only encrypted content but also encrypted personalized messages to individual users. Current broadcasting services employ an inefficient encryption scheme based on a symmetric key. Recently, several broadcast encryption schemes using a public key have been proposed in which the broadcaster encrypts a message for some subset S of users with a public key and any user in S can decrypt the broadcast with his/her private key. However, it is difficult to encrypt a personalized message and transmit it to every user efficiently. In this paper, we propose a broadcast encryption scheme that has a personalized message encryption function. We show that our scheme is efficient in terms of the ciphertext size.

Wavelet tree based watermarking algorithms are using the wavelet coefficient energy difference for copyright protection and ownership verification. WTQ (Wavelet Tree Quantization) algorithm is the representative technique using energy difference for watermarking. According to the cryptanalysis on WTQ, the watermark embedded in the protected image can be removed successfully. In this paper, we present a novel differential energy watermarking algorithm based on the wavelet tree group modulation structure, i.e. WTGM (Wavelet Tree Group Modulation). The wavelet coefficients of host image are divided into disjoint super trees (each super tree containing two sub-super trees). The watermark is embedded in the relatively high-frequency components using the group strategy such that energies of sub-super trees are close. The employment of wavelet tree structure, sum-of-subsets and positive/negative modulation effectively improve the drawbacks of the WTQ scheme for its insecurity. The integration of the HVS (Human Visual System) for WTGM provides a better visual effect of the watermarked image. The experimental results demonstrate the effectiveness of our algorithm in terms of robustness and imperceptibility.

We present a novel approach to developing Machine Learning (ML) based decoding models for extracting a watermark in the presence of attacks. Statistical characterization of the components of various frequency bands is exploited to allow blind extraction of the watermark. Experimental results show that the proposed ML based decoding scheme can adapt to suit the watermark application by learning the alterations in the feature space incurred by the attack employed.

Today, users themselves are becoming subjects of content creation. The fact that blog, wiki, and UCC have become very popular shows that users want to participate to create and modify digital content. Users who participate in composing content also want to have their copyrights on their modification parts. Thus, a copyright protection system for the content which can be modified by multiple users is required. However, the conventional DRM (Digital Rights Management) systems like OMA DRM are not suitable for the modifiable content because they do not support the content created and modified by different users. Therefore in this paper, we propose a new copyright protection system which allows each modifier of the content created and modified by multiple users to have one's own copyright. We propose data formats and protocols, and analyze the proposed system in terms of the correctness and security. Performance evaluation in the view of response time shows that the proposed system is 2 to 18 times shorter than other comparative schemes.

In recent years, digital watermarking has become a popular technique for hiding information in digital images to help protect against copyright infringement. In this paper we develop a high quality and robust watermarking algorithm that combines the advantages of block-based permutation with that of neighboring coefficient embedding. The proposed approach uses the relationship between the coefficients of neighboring blocks to hide more information into high frequency blocks without causing serious distortion to the watermarked image. In addition, an extraction method for improving robustness to mid-frequency filter attacks is proposed. Our experimental results show that the proposed approach is very effective in achieving perceptual imperceptibility. Moreover, the proposed approach is robust to a variety of signal processing operations, such as compression (JPEG), image cropping, sharpening, blurring, and brightness adjustments. The robustness is especially evident under blurring attack.

Collusion-secure codes are used for digital fingerprinting and for traitor tracing. In both cases, the goal is to prevent unauthorized copying of copyrighted material, by tracing at least one guilty user when illegal copies appear. The most well-known collusion-secure code is due to Boneh and Shaw (1995/98). In this paper we improve the decoding algorithm by using soft output from the inner decoder, and we show that this permits using significantly shorter codewords.

In recent years, digital watermarking has become a popular technique for labeling digital images by hiding secret information which can protect the copyright. The goal of this paper is to develop a DCT-based watermarking algorithm for low power and high performance. Our energy-efficient technique focuses on reducing computation required on block-based permutation. Instead of using spacial coefficients proposed by Hsu and Wu's algorithm [1], we use DCT coefficients to pair blocks directly. The approach is implemented by C language and estimated power dissipation using Wattch toolset. The experimental results show that our approach not only reduces 99% energy consumption of pairing mechanism, but also increase the PSNR by 0.414 db for the best case. Moreover, the proposed approach is robust to a variety of signal distortions, such as JPEG, image cropping, sharpening, blurring, and intensity adjusting.

This letter proposes a new asymmetric watermarking scheme. In the proposed scheme, a non-full rank matrix is applied to an embedded watermark to form an asymmetric detection watermark. To detect the embedded watermark, the watermarked signal is transformed through the matrix firstly. Then a correlation test between the detection watermark and the transformed signal is performed. This scheme allows for the public release of all information, except for the embedded watermark. The performance of the scheme is analyzed, and the simulation results demonstrate that the proposed scheme is secure and robust to some common attacks.

This paper presents a correlation-based watermarking method for video using the similarity of adjacent frames. In general, the adjacent frames of a video sequence is very similar. In the proposed scheme, we use an adjoining frame in detection process instead of an original image in the watermarking scheme of Cox et al. So the proposed method does not need an original video sequence in detection process. When a watermarked video sequence is attacked by overwriting copy or frame dropping, the pair of the frames that is not adjoining in an original video sequence is used in detection process. However, since a watermark is embedded in a part of each frame and embedding positions are different for each frame in the proposed method, we can detect the watermark even from an overwriting-copied video sequence and a frame-dropped video sequence. Experimental results show that the proposed method is robust against overwriting copy and frame dropping. Moreover, it is shown from experimental results that the method has robustness to low bitrate MPEG compression and StirMark attack.

To detect the theft of Java class files efficiently, we propose a concept of Java birthmarks, which are unique and native characteristics of every class file. For a pair of class files p and q, if q has the same birthmark as p's, q is suspected as a copy of p. Ideally, the birthmarks should satisfy the following properties: (a) preservation - the birthmarks should be preserved even if the original class file is tampered with, and (b) distinction - independent class files must be distinguished by completely different birthmarks. Taking (a) and (b) into account, we propose four types of birthmarks for Java class files. To show the effectiveness of the proposed birthmarks, we conduct three experiments. In the first experiment, we demonstrate that the proposed birthmarks are sufficiently robust against automatic program transformation (93.3876% of the birthmarks were preserved). The second experiment shows that the proposed birthmarks successfully distinguish non-copied files in a practical Java application (97.8005% of given class files were distinguished). In the third experiment, we exploit different Java compilers to confirm that the proposed Java birthmarks are core characteristics independent of compiler-specific issues.

Secure distribution of digital goods is now a significantly important issue for protecting publishers' copyrights. In this paper, we study a useful primitive for constructing a secure and efficient digital rights management system (DRM) where a server which encrypts digital content and one which issues the corresponding decryption key works independently, and existing schemes lack this property. We first argue the desired property necessary of an encryption scheme for constructing an efficient DRM, and formally define an encryption scheme as split encryption scheme containing such property. Also, we show that an efficient split encryption scheme can be constructed from any identity-based scheme. More precisely, we show an equivalence result implying that a split encryption scheme for some system parameter setting and an identity-based encryption scheme have the same primitives but for different uses. Since currently there is no identity-based encryption scheme which is based on well-known computational assumption and/or provably secure in the standard model (i.e. without the random oracle model), by reasonably tuning the system parameter, we show another construction of split encryption which is secure against chosen ciphertext attacks in the standard model assuming that decision Diffie-Hellman problem is hard to solve.

In this paper, we propose a new watermarking method which spreads an ID pattern with specific sequences and embeds it throughout the spatial domain of an image. A set of the sequences is a key for extracting the ID pattern. As an ID pattern is spread throughout an image, we can extract the ID pattern from a part of the image, that is a clipped image. We can also confirm authenticity by extracting the same ID pattern from several parts of an image. The proposed method is robust to StirMark, which is a benchmark tool to test robustness of watermarked images, as well as disturbance by noise addition and common image processing operations such as edge-enhancement, brightness-contrast conversion, posterization, Gauss filtering, median filtering, gamma correction, JPEG compression and clipping.

Recently, digital contents are copied easily because of the development of digital technology. So digital watermark technique which aims at copyright protection of digital contents becomes more and more important, and various watermarking methods have been proposed. In this paper, we proposed a method of digital watermark for still image by using wavelet packets, and examine the robustness of the watermarking method against several image processings. This method can be easily applied to the watermark for video because in this method, embedded data are detected without original image. Therefore, we extend the wavelet-based watermarking method to the case of watermark for video.