11298356
Identity-Based Threshold Decryption
In this paper, we examine issues related to the construction of identity-based threshold decryption schemes and argue that it is important in practice to design an identity-based threshold decryption scheme in which a private key associated with an identity is shared. A major contribution of this paper is to construct the first identity-based threshold decryption scheme secure against chosen-ciphertext attack. A formal proof of security of the scheme is provided in the random oracle model, assuming the Bilinear Diffie-Hellman problem is computationally hard. Another contribution of this paper is, by extending the proposed identity-based threshold decryption scheme, to construct a mediated identity-based encryption scheme secure against more powerful attacks than those considered previously.
105147
Digital Watermarking Robust Against JPEG Compression
Digital watermarking has been considered as an important technique to protect the copyright of digital content. For a digital watermarking method to be effective, it is essential that a watermark embedded in a still or moving image resists against various attacks ranging from compression, filtering to cropping. As JPEG is a dominant still image compression standard for Internet applications, digital watermarking methods that are robust against the JPEG compression are especially useful. Most digital watermarking methods proposed so far work by modulating pixels/coefficients without considering the quality level of JPEG, which renders watermarks readily removable. In this paper, we propose a new method that actively uses the JPEG quality level as a parameter in embedding a watermark into an image. A useful feature of the new method is that the watermark can be extracted even when the image is compressed using JPEG.
9346791
On the Security of RSA with Primes Sharing Least-Significant Bits
Abstract.We investigate the security of a variant of the RSA public-key cryptosystem called LSBS-RSA, in which the modulus primes share a large number of least-significant bits. We show that low public-exponent LSBS-RSA is inherently resistant to Partial Key Exposure (PKE) attacks in which least-significant bits of the secret exponent are revealed to the attacker, and in particular that the Boneh-Durfee-Frankel PKE attack [5] on low public-exponent RSA is less effective for LSBS-RSA systems than for standard RSA. On the other hand, we show that large public-exponent LSBS-RSA is more vulnerable to such attacks than standard RSA. An application to server-aided RSA signature generation is proposed.
36265866
A Security Acceleration Using XML Signcryption Scheme in Mobile Grid Web Services
Today's grid architecture encompasses a far greater breadth of applications than the traditional grid, which focused on distributed applications processing large amounts of data. Newer grid applications are more data-centric and more focused on distributed services. As these trends, mobile internet and the grid, are likely to find each other the resource constraints that wireless devices pose today affect the level of interoperability between them. The goal of this paper is to investigate how well the most limited wireless devices can make the use of grid security services. This paper describes a novel security approach on fast mobile grid services based on current mobile web services platform environment using XML signcryption mechanism.
14223982
Statistical Database Modeling for Privacy Preserving Database Generation
Testing of database applications is of great importance. Although various studies have been conducted to investigate testing techniques for database design, relatively few efforts have been made to explicitly address the testing of database applications which requires a large amount of representative data available. As testing over live production databases is often infeasible in many situations due to the high risks of disclosure of confidential information or incorrect updating of real data, in this paper we investigate the problem of generating synthetic database based on a-priori knowledge about production database. Our approach is to fit general location model using various characteristics (e.g., constraints, statistics, rules) extracted from production database and then generate synthetic data using model learnt. As characteristics extracted may contain information which may be used by attacker to derive some confidential information, we present a disclosure analysis method which is based on cell suppression technique. Our method is effective and efficient to remove aggregate private information during data generation.
7417533
Cryptographically resilient functions
This correspondence studies resilient functions which have applications in fault-tolerant distributed computing, quantum cryptographic key distribution, and random sequence generation for stream ciphers. We present a number of new methods for synthesizing resilient functions. An interesting aspect of these methods is that they are applicable both to linear and nonlinear resilient functions. Our second major contribution is to show that every linear resilient function can be transformed into a large number of nonlinear resilient functions with the same parameters. As a result, we obtain resilient functions that are highly nonlinear and have a high algebraic degree.
646545
Designing and Evaluating an XPath Dialect for Linguistic Queries
Linguistic research and natural language processing employ large repositories of ordered trees. XML, a standard ordered tree model, and XPath, its associated language, are natural choices for linguistic data and queries. However, several important expressive features required for linguistic queries are missing or hard to express in XPath. In this paper, we motivate and illustrate these features with a variety of linguistic queries. Then we propose extensions to XPath to support linguistic queries, and design an efficient query engine based on a novel labeling scheme. Experiments demonstrate that our language is not only sufficiently expressive for linguistic trees but also efficient for practical usage.
8560106
Combined spatial and temporal domain wavelet shrinkage algorithm for video denoising
A combined spatial- and temporal-domain wavelet shrinkage algorithm for video denoising is presented in this paper. The spatial-domain denoising technique is a selective wavelet shrinkage method which uses a two-threshold criteria to exploit the geometry of the wavelet subbands of each video frame, and each frame of the image sequence is spatially denoised independently of one another. The temporal-domain denoising technique is a selective wavelet shrinkage method which estimates the level of noise corruption as well as the amount of motion in the image sequence. The amount of noise is estimated to determine how much filtering is needed in the temporal-domain, and the amount of motion is taken into consideration to determine the degree of similarity between consecutive frames. The similarity affects how much noise removal is possible using temporal-domain processing. Using motion and noise level estimates, a video denoising technique is established which is robust to various levels of noise corruption and various levels of motion.
15990035
Content-based retransmission for 3-D wavelet video streaming on the Internet
Improving the QoS of video streaming with packet loss is a challenging topic of research. In this paper, we propose a novel content-based retransmission scheme to address this issue. The basic idea is to jointly consider the packets' contents and the channel conditions to optimize QoS. The goal is to deliver the best quality of video possible under the same channel condition. Using the proposed retransmission scheme, we have designed a 3D wavelet video streaming system. Simulation results show that the content-based retransmission can improve the video quality by more than 2 dB compared with the existing non-content-based delay-constrained retransmission when the channel loss rate is high.
33641222
Object tracking using the Gabor wavelet transform and the golden section algorithm
The paper presents an object tracking method for object-based video processing which uses a two-dimensional (2D) Gabor wavelet transform (GWT) and a 2D golden section algorithm. An object in the current frame is modeled by local features from a number of the selected feature points, and the global placement of these feature points. The feature points are stochastically selected based on the energy of their GWT coefficients. Points with higher energy have a higher probability of being selected since they are visually more important. The amplitudes of the GWT coefficients of a feature point are then used as the local feature. The global placement of the feature points is determined by a 2D mesh whose feature is the area of the triangles formed by the feature points. In this way, a local feature is represented by a GWT coefficient amplitude vector, and a global feature is represented by a triangle area vector. One advantage of the 2D mesh is that the direction of its triangle area vector is invariant to affine transform. Consequently, the similarity between two local features or two global features can be defined as a function of the angle and the length ratio between two vectors, and the overall similarity between two objects is a weighted sum of the local and global similarities. In order to find the corresponding object in the next frame, the 2D golden section algorithm is employed. Our results show that the method is robust to object deformation and supports object tracking in noisy video sequences.
5415824
Shared memory programming for large scale machines
This paper describes the design and implementation of a scalable run-time system and an optimizing compiler for Unified Parallel C (UPC). An experimental evaluation on BlueGene/L®, a distributed-memory machine, demonstrates that the combination of the compiler with the runtime system produces programs with performance comparable to that of efficient MPI programs and good performance scalability up to hundreds of thousands of processors.Our runtime system design solves the problem of maintaining shared object consistency efficiently in a distributed memory machine. Our compiler infrastructure simplifies the code generated for parallel loops in UPC through the elimination of affinity tests, eliminates several levels of indirection for accesses to segments of shared arrays that the compiler can prove to be local, and implements remote update operations through a lower-cost asynchronous message. The performance evaluation uses three well-known benchmarks --- HPC RandomAccess, HPC STREAM and NAS CG --- to obtain scaling and absolute performance numbers for these benchmarks on up to 131072 processors, the full BlueGene/L machine. These results were used to win the HPC Challenge Competition at SC05 in Seattle WA, demonstrating that PGAS languages support both productivity and performance.