To prove or disprove the computational equivalence of solving the RSA problem and factoring integers is a longstanding open problem in cryptography. This paper provides some evidence towards the validity of this equiv...
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ISBN:
(纸本)9783540494751
To prove or disprove the computational equivalence of solving the RSA problem and factoring integers is a longstanding open problem in cryptography. This paper provides some evidence towards the validity of this equivalence. We show that any efficient generic ring algorithm which solves the (flexible) low-exponent RSA problem can be converted into an efficient factoring algorithm. Thus, the low-exponent RSA problem is intractable w.r.t. generic ring algorithms provided that factoring is hard.
The non-destructive and automatic 3D surface analysis using white-light interferometry has very high demands on the required computing systems. This is due to both, the high volume of data that are collected and the t...
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ISBN:
(纸本)9783319091471;9783319091464
The non-destructive and automatic 3D surface analysis using white-light interferometry has very high demands on the required computing systems. This is due to both, the high volume of data that are collected and the tremendous computational power, required by algorithms which evaluate the data. Furthermore, material characteristics and environmental influences like temperature or ambient light have a not negligible effect on the scan procedure, such that the algorithmic approaches must be adjusted to assess the correct surface profile. Thus, to obtain the desired analysis results and to fulfill the computational requirements, the application developer has to consider the physical characteristics of the white-light interferometry process as well as the attributes of the computational platform used. This paper describes the generic computational module of a new framework for the white-light interferometry surface scanning procedure to address these problems. This framework allows a user-transparent automatic assessment and usage of available computational resources.
We describe two improvements to introspective sorting and selection algorithms: a simple rule fine-grained introspection that detects potential worst-case performance after only a small constant number of partitioning...
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We describe two improvements to introspective sorting and selection algorithms: a simple rule fine-grained introspection that detects potential worst-case performance after only a small constant number of partitioning steps, and the use of remedial randomization as an intervention strategy in order to reduce the performance penalty for false positives. We present experimental results showing that these techniques provide significant improvements in the running time for worst-case and other troublesome inputs, without sacrificing performance on well-behaved inputs. Copyright (C) 2000 John Wiley & Sons, Ltd.
Let N be a random variable distributed according to some appropriate distribution over the set of products of two primes, such that factoring N is believed to be hard. The RSA assumption states that, given an a chosen...
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Let N be a random variable distributed according to some appropriate distribution over the set of products of two primes, such that factoring N is believed to be hard. The RSA assumption states that, given an a chosen uniformly at random from Z(N) and an e is an element of N \ {1} such that gcd(e, phi(N)) = 1, it is computationally hard to find an x is an element of Z(N) such that x(e) - a = 0 (mod N). When complexity-theoretic (relative) lower bounds for certain cryptographic problems in a general model of computation seem to elude discovery, a common practice in cryptography is to give proofs of computational security in meaningful restricted models of computation. An example of such a restricted model that is interesting in cryptography is the generic group model that has been used for proving lower bounds for the discrete logarithm problem and other related problems. A generic model captures that an algorithm does not exploit the bit representation of the elements other than for testing equality. In this paper, we prove that the problem of factoring N can be efficiently reduced to solving the RSA problem on ZN in the generic ring model of computation, where an algorithm can perform ring operations, inverse ring operations, and test equality. This provides evidence toward the soundness of the RSA encryption and digital signature scheme, in particular showing that under the factoring assumption, they are not vulnerable to certain kinds of cryptanalytic attacks.
We study algorithms in the LOCAL model that produce secured output. Specifically, each vertex computes its part in the output, the entire output is correct, but each vertex cannot discover the output of other vertices...
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We study algorithms in the LOCAL model that produce secured output. Specifically, each vertex computes its part in the output, the entire output is correct, but each vertex cannot discover the output of other vertices, with a certain probability. As the extensive research in the distributed algorithms field yielded efficient decentralized algorithms, the discussion about the security of distributed algorithms was somewhat neglected. Nevertheless, many protocols and algorithms were devised in the research area of secure multi-party computation problem. However, the focus in those protocols was to work for every function f at the expense of increasing the round complexity, or the necessity of several computational assumptions. We present a novel approach, which identifies and develops those algorithms that are inherently secure (which means they do not require any further constructions). This approach yields efficient secure algorithms for various labeling and decomposition problems without requiring any hardness assumption, but only a private randomness generator in each vertex.(c) 2022 Elsevier Inc. All rights reserved.
Let G be a group of prime order q with generator g. We study hardcore subsets H subset of G of the discrete logarithm (DL) log(g) in the model of generic algorithms. In this model we count group operations such as mul...
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Let G be a group of prime order q with generator g. We study hardcore subsets H subset of G of the discrete logarithm (DL) log(g) in the model of generic algorithms. In this model we count group operations such as multiplication and division, while computations with non-group data are for free. It is known from Nechaev [Math. Notes 55 (1994) 165] and Shoup [Lecture Notes in Comp. Sci., Vol. 1233, Springer, Berlin, 1997, p. 256] that generic DL-algorithms for the entire group G must perform root 2q generic steps. We show that DL-algorithms for small subsets H subset of G require 1/2m + o(m) generic steps for almost all H of size #H = m with m less than or equal to rootq. Conversely, 1/2m + 1 generic steps are sufficient for all H subset of G of even size m. Our main result justifies to generate secret DL-keys from seeds that are only 1/2 log(2) q bits long. (C) 2001 Elsevier Science B.V. All rights reserved.
To increase the evolvability of larger search spaces, several indirect encoding strategies have been proposed. Among these, multicellular developmental systems are believed to offer great potential for the evolution o...
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To increase the evolvability of larger search spaces, several indirect encoding strategies have been proposed. Among these, multicellular developmental systems are believed to offer great potential for the evolution of general, scalable, and self-repairing organisms. We reinforce this view, presenting the results achieved by such a model and comparing it against direct encoding. Extra effort has been made to make this comparison both general and meaningful. Embryonal stages, a generic method showing increased evolvability and applicable to any developmental model, are introduced. Development with embryonal stages implements what we refer to as direct neutral complexification: direct genotype complexification by neutral duplication of expressed genes. The results show that, even for high-complexity evolutionary targets, the developmental model proves more scalable. The model also shows emergent self-repair, which is used to produce highly resilient organisms.
A novel dermoscopy image segmentation algorithm is proposed using a combination of a self-generating neural network (SGNN) and the genetic algorithm (GA). Optimal samples are selected as seeds using GA;taking these se...
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A novel dermoscopy image segmentation algorithm is proposed using a combination of a self-generating neural network (SGNN) and the genetic algorithm (GA). Optimal samples are selected as seeds using GA;taking these seeds as initial neuron trees, a self-generating neural forest (SGNF) is generated by training the rest of the samples using SGNN. Next the number of clusters is determined by optimizing the SD index of cluster validity, and clustering is completed by treating each neuron tree as a cluster. Since SGNN often delivers inconsistent cluster partitions owing to sensitivity relative to the input order of the training samples, GA is combined with SGNN to optimize and stabilize the clustering result. In the post-processing phase, the clusters are merged into lesion and background skin, yielding the segmented dermoscopy image. A series of experiments on the proposed model and the other automatic segmentation methods (including Otsu's thresholding method, k-means, fuzzy c-means (FCM) and statistical region merging (SRM)) reveals that the optimized model delivers better accuracy and segmentation results. (C) 2012 Elsevier Ltd. All rights reserved.
Constraint propagation algorithms form an important part of most of the constraint programming systems. We provide here a simple, yet very general framework that allows us to explain several constraint propagation alg...
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Constraint propagation algorithms form an important part of most of the constraint programming systems. We provide here a simple, yet very general framework that allows us to explain several constraint propagation algorithms in a systematic way. In this framework we proceed in two steps. First, we introduce a generic iteration algorithm on partial orderings and prove its correctness in an abstract setting. Then we instantiate this algorithm with specific partial orderings and functions to obtain specific constraint propagation algorithms. In particular, using the notions commutativity and semi-commutativity, we show that the AC-3, PC-2, DAC, and DPC algorithms for achieving (directional) are consistency and (directional) path consistency are instances of a single generic algorithm. The work reported here extends and simplifies that of Apt [1999a].
作者:
Apt, KRCWI
NL-1009 AB Amsterdam Netherlands Univ Amsterdam
Dept Math Comp Sci Phys & Astron NL-1012 WX Amsterdam Netherlands
We show that several constraint propagation algorithms (also called (local) consistency, consistency enforcing, Waltz, filtering or narrowing algorithms) are instances of algorithms that deal with chaotic iteration. T...
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We show that several constraint propagation algorithms (also called (local) consistency, consistency enforcing, Waltz, filtering or narrowing algorithms) are instances of algorithms that deal with chaotic iteration. To this end we propose a simple abstract framework that allows us to classify and compare these algorithms and to establish in a uniform way their basic properties. (C) 1999 Elsevier Science B.V. All rights reserved.
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