455 research outputs found
Hardware Implementation of a Secured Digital Camera with Built In Watermarking and Encryption Facility
The objective is to design an efficient hardware implementation of a secure digital camera for real time digital rights management (DRM) in embedded systems incorporating watermarking and encryption. This emerging field addresses issues related to the ownership and intellectual property rights of digital content. A novel invisible watermarking algorithm is proposed which uses median of each image block to calculate the embedding factor. The performance of the proposed algorithm is compared with the earlier proposed permutation and CRT based algorithms. It is seen that the watermark is successfully embedded invisibly without distorting the image and it is more robust to common image processing techniques like JPEG compression, filtering, tampering. The robustness is measured by the different quality assessment metrics- Peak Signal to Noise Ratio (PSNR), Normalized Correlation (NC), and Tampering Assessment Function (TAF). It is simpler to implement in hardware because of its computational simplicity. Advanced Encryption Standard (AES) is applied after quantization for increased security. The corresponding hardware architectures for invisible watermarking and AES encryption are presented and synthesized for Field Programmable Gate Array(FPGA).The soft cores in the form of Hardware Description Language(HDL) are available as intellectual property cores and can be integrated with any multimedia based electronic appliance which are basically embedded systems built using System On Chip (SoC) technology
Region-Based Watermarking of Biometric Images: Case Study in Fingerprint Images
In this paper, a novel scheme to watermark biometric
images is proposed. It exploits the fact that biometric
images, normally, have one region of interest, which represents
the relevant part of information processable by most of the
biometric-based identification/authentication systems. This proposed
scheme consists of embedding the watermark into the
region of interest only; thus, preserving the hidden data from
the segmentation process that removes the useless background
and keeps the region of interest unaltered; a process which can
be used by an attacker as a cropping attack. Also, it provides
more robustness and better imperceptibility of the embedded
watermark. The proposed scheme is introduced into the optimum
watermark detection in order to improve its performance. It is
applied to fingerprint images, one of the most widely used and
studied biometric data. The watermarking is assessed in two
well-known transform domains: the discrete wavelet transform
(DWT) and the discrete Fourier transform (DFT). The results
obtained are very attractive and clearly show significant improvements
when compared to the standard technique, which
operates on the whole image. The results also reveal that the
segmentation (cropping) attack does not affect the performance
of the proposed technique, which also shows more robustness
against other common attacks
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Protection of an intrusion detection engine with watermarking in ad hoc networks
Mobile ad hoc networks have received great attention in recent years, mainly due to the evolution of wireless networking and mobile computing hardware. Nevertheless, many inherent vulnerabilities exist in mobile ad hoc networks and their applications that affect the security of wireless transactions. As intrusion prevention mechanisms, such as encryption and authentication, are not sufficient we need a second line of defense, Intrusion Detection. In this pa-per we present an intrusion detection engine based on neural networks and a protection method based on watermarking techniques. In particular, we exploit information visualization and machine learning techniques in order to achieve intrusion detection and we authenticate the maps produced by the application of the intelligent techniques using a novel combined watermarking embedding method. The performance of the proposed model is evaluated under different traffic conditions, mobility patterns and visualization metrics
Forensic Analysis of Digital Image Tampering
The use of digital photography has increased over the past few years, a trend which opens the door for new and creative ways to forge images. The manipulation of images through forgery influences the perception an observer has of the depicted scene, potentially resulting in ill consequences if created with malicious intentions. This poses a need to verify the authenticity of images originating from unknown sources in absence of any prior digital watermarking or authentication technique. This research explores the holes left by existing research; specifically, the ability to detect image forgeries created using multiple image sources and specialized methods tailored to the popular JPEG image format. In an effort to meet these goals, this thesis presents four methods to detect image tampering based on fundamental image attributes common to any forgery. These include discrepancies in 1) lighting and 2) brightness levels, 3) underlying edge inconsistencies, and 4) anomalies in JPEG compression blocks. Overall, these methods proved encouraging in detecting image forgeries with an observed accuracy of 60% in a completely blind experiment containing a mixture of 15 authentic and forged images
Image watermarking based on the space/spatial-frequency analysis and Hermite functions expansion
International audienceAn image watermarking scheme that combines Hermite functions expansion and space/spatial-frequency analysis is proposed. In the first step, the Hermite functions expansion is employed to select busy regions for watermark embedding. In the second step, the space/spatial-frequency representation and Hermite functions expansion are combined to design the imperceptible watermark, using the host local frequency content. The Hermite expansion has been done by using the fast Hermite projection method. Recursive realization of Hermite functions significantly speeds up the algorithms for regions selection and watermark design. The watermark detection is performed within the space/spatial-frequency domain. The detection performance is increased due to the high information redundancy in that domain in comparison with the space or frequency domains, respectively. The performance of the proposed procedure has been tested experimentally for different watermark strengths, i.e., for different values of the peak signal-to-noise ratio (PSNR). The proposed approach provides high detection performance even for high PSNR values. It offers a good compromise between detection performance (including the robustness to a wide variety of common attacks) and imperceptibility
High Dynamic Range Image Watermarking Robust Against Tone-Mapping Operators
High dynamic range (HDR) images represent the future format for digital images since they allow accurate rendering of a wider range of luminance values. However, today special types of preprocessing, collectively known as tone-mapping (TM) operators, are needed to adapt HDR images to currently existing displays. Tone-mapped images, although of reduced dynamic range, have nonetheless high quality and hence retain some commercial value. In this paper, we propose a solution to the problem of HDR image watermarking, e.g., for copyright embedding, that should survive TM. Therefore, the requirements imposed on the watermark encompass imperceptibility, a certain degree of security, and robustness to TM operators. The proposed watermarking system belongs to the blind, detectable category; it is based on the quantization index modulation (QIM) paradigm and employs higher order statistics as a feature. Experimental analysis shows positive results and demonstrates the system effectiveness with current state-of-art TM algorithms
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