11596303
A Practical Digital Multisignature Scheme Based on Discrete Logarithms
This paper proposes a practical digital multisignature scheme based on the C sig * cryptosystem derived from the C sig cryptosystem of Zheng and Seberry (1993). The simple scheme consists of three phases. In the first phase the issuer of the document prepares the document, the list of prospective signatories and a pad on which signatories are to write their signatures. In the second phase each signatory verifies the document, signs it and forwards it to the next signatory. In the third phase a trusted verifier or notary decides on the validity of the signatures. The scheme prevents cheating by dishonest signatories from going undetected. The scheme is practical and offers at least the same security level afforded by its underlying cryptosystem against external attacks. Internal attacks in the form of forging or cheating by a dishonest issuer or by one or more of the signatories (alone or by collaboration) requires the solving of instances of the discrete logarithm problem.
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.
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.
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.
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.
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.
11180883
An approach to multimodal biomedical image registration utilizing particle swarm optimization
Biomedical image registration, or geometric alignment of two-dimensional and/or three-dimensional (3D) image data, is becoming increasingly important in diagnosis, treatment planning, functional studies, computer-guided therapies, and in biomedical research. Registration based on intensity values usually requires optimization of some similarity metric between the images. Local optimization techniques frequently fail because functions of these metrics with respect to transformation parameters are generally nonconvex and irregular and, therefore, global methods are often required. In this paper, a new evolutionary approach, particle swarm optimization, is adapted for single-slice 3D-to-3D biomedical image registration. A new hybrid particle swarm technique is proposed that incorporates initial user guidance. Multimodal registrations with initial orientations far from the ground truth were performed on three volumes from different modalities. Results of optimizing the normalized mutual information similarity metric were compared with various evolutionary strategies. The hybrid particle swarm technique produced more accurate registrations than the evolutionary strategies in many cases, with comparable convergence. These results demonstrate that particle swarm approaches, along with evolutionary techniques and local methods, are useful in image registration, and emphasize the need for hybrid approaches for difficult registration problems.
2310959
XKvalidator: a constraint validator for XML
The role of XML in data exchange is evolving from one of merely conveying the structure of data to one that also conveys its semantics. In particular, several proposals for key and foreign key constraints have recently appeared, and aspects of these proposals have been adopted within XMLSchema.In this paper, we examine the problem of checking keys and foreign keys in XML documents using a validator based on SAX. The algorithm relies on an indexing technique based on the paths found in key definitions, and can be used for checking the correctness of an entire document (bulk checking) as well as for checking updates as they are made to the document (incremental checking). The asymptotic performance of the algorithm is linear in the size of the document or update. Furthermore, experimental results demonstrate reasonable performance.
1196113
Feature-based wavelet shrinkage algorithm for image denoising
A selective wavelet shrinkage algorithm for digital image denoising is presented. The performance of this method is an improvement upon other methods proposed in the literature and is algorithmically simple for large computational savings. The improved performance and computational speed of the proposed wavelet shrinkage algorithm is presented and experimentally compared with established methods. The denoising method incorporated in the proposed algorithm involves a two-threshold validation process for real-time selection of wavelet coefficients. The two-threshold criteria selects wavelet coefficients based on their absolute value, spatial regularity, and regularity across multiresolution scales. The proposed algorithm takes image features into consideration in the selection process. Statistically, most images have regular features resulting in connected subband coefficients. Therefore, the resulting subbands of wavelet transformed images in large part do not contain isolated coefficients. In the proposed algorithm, coefficients are selected due to their magnitude, and only a subset of those selected coefficients which exhibit a spatially regular behavior remain for image reconstruction. Therefore, two thresholds are used in the coefficient selection process. The first threshold is used to distinguish coefficients of large magnitude and the second is used to distinguish coefficients of spatial regularity. The performance of the proposed wavelet denoising technique is an improvement upon several other established wavelet denoising techniques, as well as being computationally efficient to facilitate real-time image-processing applications.
9136723
Biped Locomotion by Reduced Ankle Power
Power reduction in the ankle joints of a biped robot is considered inthis paper. Ankles of human beings have small torque and are veryflexible within a certain range of motion (very stiff near and beyondthis range). This characteristic makes foot landing soft and gives agood contact between its sole and the ground. This feature can beimplemented in a biped robot by using a small actuator for the anklejoints. A small actuator consumes less energy and reduces the weightof the leg. With less power in the ankle joints, robot walkingbecomes more difficult to control. This problem can be solved byproviding a feedback control mechanism as presented in this paper. Thecontrol mechanism uses the motion of the body and the swinging leg toeliminate instability caused by the weak ankle. Two locomotionexamples, standing and walking, were investigated respectively toshow the validity of the proposed control scheme. In standing, thecontrol input is the displacement of the ankle joint of thesupporting leg. The control mechanism decides the bending angle ofthe body and the position of the swinging leg. For walking, only thebending angle of the body is used to avoid the discontinuity of thecontrol input. Experimental results are presented to show theeffectiveness of the control mechanism.