15419333
Structural Properties of One-way Hash Functions
We study the following two kinds of one-way hash functions: universal one-way hash functions (UOHs) and collision intractable hash functions (CIHs). The main property of the former is that given an initial-string x, it is computationally difficult to find a different string y that collides with x. And the main property of the latter is that it is computationally difficult to find a pair x ? y of strings such that x collides with y. Our main results are as follows. First we prove that UOHs with respect to initial-strings chosen arbitrarily exist if and only if UOHs with respect to initial-strings chosen uniformly at random exist. Then, as an application of the result, we show that UOHs with respect to initial-strings chosen arbitrarily can be constructed under a weaker assumption, the existence of one-way guasi-injections. Finally, we investigate relationships among various versions of one-way hash functions. We prove that some versions of one-way hash functions axe strictly included in others by explicitly constructing hash functions that are one-way in the sense of the former but not in the sense of the latter.
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.
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.
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.
46651638
Packed integer wavelet transform constructed by lifting scheme
A new method for speeding up the integer wavelet transforms constructed by the lifting scheme is proposed. The proposed method packs multiple pixels (wavelet coefficients) in a single word; therefore, it can make use of the 32-bit or 64-bit computational capability of modern computers to accomplish multiple addition/subtraction operations in one instruction cycle. As a result, our method can save the decomposition/reconstruction time by up to 37% on 32-bit machines and require much less working memory in comparison with the original wavelet transform algorithms.
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.
38543445
3-D maximum likelihood reconstructions of viruses from cryo electron microscope images and parallel computation
A statistical method for computing 3-D reconstructions of virus particles from cryo electron microscope images and minimal prior information - particle symmetry and radii - is described. Two different approaches for parallel implementation of the algorithm are described based on parallel processing of different images and based on parallel numerical integration and numerical results showing nearly linear speedup are presented.
16436338
Applying Decomposition Methods to Crossword Puzzle Problems
Structural decomposition methods have been proposed for identifying tractable Constraint Satisfaction Problems (CSPs)[1-5]. The basic principle is to decompose a CSP into tree-structured sub-problems. The subproblems are solved independently, then the original CSP is solved in a backtrack-free manner after the tree structure is made arc-consistent, as described in [1]. In [5], we proposed four decomposition methods: HINGE+, CUT, TRAVERSE, and CaT and tested these methods on randomly generated CSPs. We compare these techniques on instances of the fully interlocked Crossword Puzzle Problems (CPPs) [6] taken from a public library [7] and identify special cases of the constraint hypergraphs where some decomposition techniques yield better results than others although in general the opposite holds. Our future work includes: 1)Identifying more such configurations, and building hybrid decompositions techniques that exploit this information; 2)Tailoring existing decomposition methods for fully interlocked CPPs so that every sub-problem, after backtrack search, has few solutions; and 3)Designing a heuristic for applying local search for fully interlocked CPPs. This work is supported by CAREER Award #0133568 from the National Science Foundation.
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.