排序方式: 共有84条查询结果,搜索用时 46 毫秒
31.
In 2004, Lee et al. [C.C. Lee, M.S. Hwang, W.P. Yang, A new blind signature based on the discrete logarithm problem for untraceability, Appl. Math. Comput., in press] proposed a new untraceable blind signature based on DLP in order to overcome the “security limits” of Carmenisch et al.’s scheme. However, we show there are two mistakes in [C.C. Lee, M.S. Hwang, W.P. Yang, A new blind signature based on the discrete logarithm problem for untraceability, Appl. Math. Comput., in press]: 1. The Carmenisch et al.’s scheme does meet the requirement of untraceability and the cryptanalysis proposed by Lee et al. is not correct; 2. Though Lee et al.’s scheme is untraceable, the proof of its untraceability in [C.C. Lee, M.S. Hwang, W.P. Yang, A new blind signature based on the discrete logarithm problem for untraceability, Appl. Math. Comput., in press] is wrong (in this paper we also give the correct proof of its untraceability). So Lee et al.’s scheme does not have any advantage and it is unpractical since the cost of the scheme is higher compared with Carmenisch et al.’s scheme. 相似文献
32.
Mun-Kyu Lee Yoonjeong Kim Kunsoo Park Yookun Cho 《Journal of Algorithms in Cognition, Informatics and Logic》2005,54(2):205-221
Von zur Gathen proposed an efficient parallel exponentiation algorithm in finite fields using normal basis representations. In this paper we present a processor-efficient parallel exponentiation algorithm in GF(qn) which improves upon von zur Gathen's algorithm. We also show that exponentiation in GF(qn) can be done in O((log2n)2/logqn) time using n/(log2n)2 processors. Hence we get a processor-time bound of O(n/logqn), which matches the best known sequential algorithm. Finally, we present an efficient on-line processor assignment scheme which was missing in von zur Gathen's algorithm. 相似文献
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34.
We report experimental evidence of mixed synchronization in two unidirectionally coupled chaotic oscillators using a scalar coupling. In this synchronization regime, some of the state variables may be in complete synchronization while others may be in anti-synchronization state. We extended the theory by using an adaptive controller with an updating law based on Lyapunov function stability to include parameter fluctuation. Using the scheme, we implemented a cryptographic encoding for digital signal through parameter modulation. 相似文献
35.
A. Kanso M. Ghebleh 《Communications in Nonlinear Science & Numerical Simulation》2012,17(7):2943-2959
Recently [Solak E, Çokal C, Yildiz OT Biyikogˇlu T. Cryptanalysis of Fridrich’s chaotic image encryption. Int J Bifur Chaos 2010;20:1405-1413] cryptanalyzed the chaotic image encryption algorithm of [Fridrich J. Symmetric ciphers based on two-dimensional chaotic maps. Int J Bifur Chaos 1998;8(6):1259-1284], which was considered a benchmark for measuring security of many image encryption algorithms. This attack can also be applied to other encryption algorithms that have a structure similar to Fridrich’s algorithm, such as that of [Chen G, Mao Y, Chui, C. A symmetric image encryption scheme based on 3D chaotic cat maps. Chaos Soliton Fract 2004;21:749-761]. In this paper, we suggest a novel image encryption algorithm based on a three dimensional (3D) chaotic map that can defeat the aforementioned attack among other existing attacks. The design of the proposed algorithm is simple and efficient, and based on three phases which provide the necessary properties for a secure image encryption algorithm including the confusion and diffusion properties. In phase I, the image pixels are shuffled according to a search rule based on the 3D chaotic map. In phases II and III, 3D chaotic maps are used to scramble shuffled pixels through mixing and masking rules, respectively. Simulation results show that the suggested algorithm satisfies the required performance tests such as high level security, large key space and acceptable encryption speed. These characteristics make it a suitable candidate for use in cryptographic applications. 相似文献
36.
The nonadjacent form method of Koblitz [Advances in Cryptology (CRYPTO'98), in: Lecture Notes in Comput. Sci., vol. 1462, 1998, pp. 327–337] is an efficient algorithm for point multiplication on a family of supersingular curves over a finite field of characteristic 3. In this paper, a further discussion of the method is given. A window nonadjacent form method is proposed and its validity is proved. Efficient reduction and pre-computations are given. Analysis shows that more than 30% of saving can be achieved. 相似文献
37.
We determine exact values for the k-error linear complexity L
k
over the finite field
of the Legendre sequence
of period p and the Sidelnikov sequence
of period p
m
− 1. The results are
for 1 ≤ k ≤ (p
m
− 3)/2 and
for k≥ (p
m
− 1)/2. In particular, we prove
相似文献
38.
Image encryption based on the multiple-parameter discrete fractional Fourier transform and chaos function 总被引:1,自引:0,他引:1
In recent years, the chaos-based cryptographic algorithms have suggested some new and efficient ways to develop secure image encryption techniques. In this paper, we propose a new approach for image encryption based on the multiple-parameter discrete fractional Fourier transform and chaotic logistic maps in order to meet the requirements of the secure image transmission. In the proposed image encryption scheme, the image is encrypted by juxtaposition of sections of the image in the multiple-parameter discrete fractional Fourier domains and the alignment of sections is determined by chaotic logistic maps. This method does not require the use of phase keys. The new method has been compared with several existing methods and shows comparable or superior robustness to blind decryption. 相似文献
39.
A secret sharing scheme based on cellular automata 总被引:3,自引:0,他引:3
A. Martín del Rey J. Pereira Mateus G. Rodríguez Snchez 《Applied mathematics and computation》2005,170(2):27-1364
A new secret sharing scheme based on a particular type of discrete delay dynamical systems: memory cellular automata, is proposed. Specifically, such scheme consists of a (k, n)-threshold scheme where the text to be shared is considered as one of the k initial conditions of the memory cellular automata and the n shares to be distributed are n consecutive configurations of the evolution of such cellular automata. It is also proved to be perfect and ideal. 相似文献
40.
Zuhua Shao 《Applied mathematics and computation》2005,170(2):976
To enhance the security of signature schemes, Pon et al., recently, investigated all eight variants of the He’s digital signature scheme. The security of the proposed schemes is based on the difficulties of simultaneously solving the factoring and discrete logarithm problems with almost the same sizes of arithmetic modulus. This paper shows that the all eight variants of the He’s digital signature scheme, as well as two more variants, are not secure if attackers can solve discrete logarithm problems. Moreover, the attackers can easily forge signatures of the most optimal signature schemes of the generalized He’ signature schemes even though they can solve neither discrete logarithm problems nor factoring. 相似文献