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Carlet C.,University of Paris 13 | Gao G.,State Key Laboratory of Mathematical Engineering and Advanced Computing | Gao G.,Beijing University of Posts and Telecommunications | Liu W.,State Key Laboratory of Mathematical Engineering and Advanced Computing | Liu W.,Beijing University of Posts and Telecommunications
Journal of Combinatorial Theory. Series A | Year: 2014

We study more in detail the relationship between rotation symmetric (RS) functions and idempotents, in univariate and bivariate representations, and deduce a construction of bent RS functions from semi-bent RS functions. We deduce the first infinite classes found of idempotent and RS bent functions of algebraic degree more than 3. We introduce a transformation from any RS Boolean function f over GF(2)n into the idempotent Boolean function f'(z)=f(z,z2,. . .,z2n-1) over GF(2n), leading to another RS Boolean function. The trace representation of f ' is directly deduced from the algebraic normal form of f, but we show that f and f ', which have the same algebraic degree, are in general not affinely equivalent to each other. We exhibit infinite classes of functions f such that (1) f is bent and f ' is not (2) f ' is bent and f is not (3) f and f ' are both bent (we show that this is always the case for quadratic functions and we also investigate cubic functions). © 2014 Elsevier Inc.

Yuan H.-D.,Henan Institute of Science and Technology | Yuan H.-D.,State Key Laboratory of Mathematical Engineering and Advanced Computing
Information Sciences | Year: 2014

More and more studies have been dedicated to investigating secret sharing with steganography. Unfortunately, no previous work has ever reported its capability to resist steganalysis. In this paper, we pose the multi-cover adaptive steganography problem. Two secret sharing methods for natural images based on multi-cover adaptive steganography have been proposed. The secret information is adaptively shared into textured regions of covers by a spatial ±1 operation. In comparison to previous secret sharing methods, each of the proposed methods uses a simple share-constructing operation and each has lossless secret reconstruction and high quality shares. More importantly, the proposed methods are more secure in terms of resistance against state-of-The-Art steganalysis techniques. In comparison to previous steganographic methods, the proposed methods hide secret bits among textured regions with different covers and are thus difficult to detect. Moreover, the proposed methods can be used to adaptively embed location-sensitive secrets (e.g., secret images) and require no stego key for extracting the encrypted message. These results also have significance in individual cover steganography. The experimental results show the effectiveness of the proposed methods. © 2013 Elsevier Inc. All rights reserved.

Sun S.-H.,National University of Defense Technology | Gao M.,State Key Laboratory of Mathematical Engineering and Advanced Computing | Li C.-Y.,National University of Defense Technology | Liang L.-M.,National University of Defense Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

Measurement-device-independent quantum key distribution (MDI-QKD) is immune to all the detection attacks; thus when it is combined with the decoy-state method, the final key is unconditionally secure, even if a practical weak coherent source is used by Alice and Bob. However, until now, the analysis of decoy-state MDI-QKD with a weak coherent source is incomplete. In this paper, we derive, with only vacuum+weak decoy state, some tight formulas to estimate the lower bound of yield and the upper bound of error rate for the fraction of signals in which both Alice and Bob send a single-photon pulse to the untrusted third party Charlie. The numerical simulations show that our method with only vacuum+weak decoy state can asymptotically approach the theoretical limit of the infinite number of decoy states. Furthermore, the statistical fluctuation due to the finite length of date is also considered based on the standard statistical analysis. © 2013 American Physical Society.

Sun W.J.,State Key Laboratory of Mathematical Engineering and Advanced Computing
Applied Mechanics and Materials | Year: 2014

Chaos is a similar and random process which is very sensitive to initial value in deterministic system. It is a performance of nonlinear dynamical system with built-in randomness. Combined with the advantages and disadvantages of the present chaos encryption model, the paper proposes a chaotic stream cipher model based on chaos theory, which not only overcomes finite precision effect, but also improves the randomness of chaotic system and output sequence. The Sequence cycle theory generated by the algorithm can reach more than 10600 at least, which completely satisfies the actual application requirements of stream cipher system. © (2014) Trans Tech Publications, Switzerland.

Sun W.J.,State Key Laboratory of Mathematical Engineering and Advanced Computing
Applied Mechanics and Materials | Year: 2014

Replacement and substitution encryption are two basic types of encryption historically. The classical encryption algorithm has been compromised now, but they still can play special role for modern cryptology. For example, in digital image encryption system, substitution can disrupt the original order of the images and eliminate the correlation of image information which not only can realize security of images, but also can resist intentional attack and destruction of clipping and noise. And transposition transformation is introduced into the design of block ciphers. The substitution has the feature of high efficiency and resistance, which makes it meet the specific requirements of encryption. So substitution cypher can be applied to modern encryption system. © (2014) Trans Tech Publications, Switzerland.

Yi W.,State Key Laboratory of Mathematical Engineering and Advanced Computing | Chen S.,State Key Laboratory of Mathematical Engineering and Advanced Computing
IET Information Security | Year: 2016

The block cipher KASUMI, proposed by ETSI SAGE over 10 years ago, is widely used for security in many synchronous wireless standards nowadays. For instance, the confidentiality and integrity of 3G mobile communications systems depend on the security of KASUMI. Up to now, there is a great deal of cryptanalytic results on KASUMI. However, its security evaluation against the recent zero-correlation linear attacks is still lacking. In this study, combining with some observations on the FL, FO and FI functions, the authors select some special input/output masks to refine the general 5-round zero-correlation linear approximations and propose the 6-round zero-correlation linear attack on KASUMI. Moreover, under the weak key conditions that the second keys of the FL function in rounds 2 and 8 have the same values at 1st-8th and 11th-16th bit-positions, they expand the attack to 7-round KASUMI (2-8). These weak keys take 1/214 of the key space. The new zero-correlation linear attack on the 6-round needs about 2118 encryptions with 262.9 known plaintexts and 254 bytes memory. For the attack under weak keys conditions on the last 7 rounds, the data complexity is about 262.1 known plaintexts, and the time complexity is about 2110.5 encryptions, and the memory requirement is about 285 bytes. © The Institution of Engineering and Technology 2016.

Hu X.,Information Assurance | Hu X.,State Key Laboratory of Mathematical Engineering and Advanced Computing | Zhang Z.,Information Assurance
Nonlinear Dynamics | Year: 2014

Recently, Lee et al. (Nonlinear Dyn, 73(1–2):125–132, 2013) proposed a three party password authenticated key exchange with user anonymity by utilizing extended chaotic maps. They claimed that their protocol is more secure than previously proposed schemes. In this paper, our analysis shows that Lee et al.’s protocol suffers from two kinds of attacks: (1) man-in-the-middle attack, and (2) user anonymity attack. To overcome these weakness, we propose an enhanced protocol that can resist the attacks described and yet with comparable efficiency. © 2014, Springer Science+Business Media Dordrecht.

Liang S.,CAS Academy of Mathematics and Systems Science | Liang S.,Chinese Academy of Sciences | Liang S.,State Key Laboratory of Mathematical Engineering and Advanced Computing | Liu W.,CAS Academy of Mathematics and Systems Science | Yuan L.,CAS Academy of Mathematics and Systems Science
Computers and Fluids | Year: 2014

In this paper, the application of an HLLC-type approximate Riemann solver in conjunction with the third-order TVD Runge-Kutta method to the seven-equation compressible two-phase model on multiple Graphics Processing Units (GPUs) is presented. Based on the idea proposed by Abgrall et al. that "a multiphase flow, uniform in pressure and velocity at t = 0, will remain uniform on the same variables during time evolution", discretization schemes for the non-conservative terms and for the volume fraction evolution equation are derived in accordance with the HLLC solver used for the conservative terms. To attain high temporal accuracy, the third-order TVD Runge-Kutta method is implemented in conjunction with operator splitting technique, in which the sequence of operators is recorded in order to compute free surface problems robustly. For large scale simulations, the numerical method is implemented using MPI/Pthread-CUDA parallelization paradigm for multiple GPUs. Domain decomposition method is used to distribute data to different GPUs, parallel computation inside a GPU is accomplished using CUDA, and communication between GPUs is performed via MPI or Pthread. Efficient data structure and GPU memory usage are employed to maintain high memory bandwidth of the device, while a special procedure is designed to synchronize thread blocks so as to reduce frequencies of kernel launching. Numerical tests against several one- and two-dimensional compressible two-phase flow problems with high density and high pressure ratios demonstrate that the present method is accurate and robust. The timing tests show that the overall speedup of one NVIDIA Tesla C2075 GPU is 31× compared with one Intel Xeon Westmere 5675 CPU core, and nearly 70% parallel efficiency can be obtained when using 8 GPUs. © 2014 Elsevier Ltd.

Li Q.,State Key Laboratory of Mathematical Engineering and Advanced Computing | Zhang P.,State Key Laboratory of Mathematical Engineering and Advanced Computing
10th International Conference on Computer Science and Education, ICCSE 2015 | Year: 2015

Arithmetic unit design has been one of the important and difficult parts in teaching of principles of computer organization course and is hard for students to understand and master. Because teaching of arithmetic unit design is usually began with examining the process of computer arithmetic, many students are apt to think it as numerical calculation and don't really understand the main idea in computer design of simplification, normalization and rapid processing. In this paper, we reveal the basic idea of computer arithmetic unit design by the analysis of data representation and the process of calculation, taking addition, subtraction and multiplication as example. Based on the background of our many years' teaching and research, we discuss some effective heuristic methods in teaching of arithmetic unit design. © 2015 IEEE.

Wei J.,State Key Laboratory of Mathematical Engineering and Advanced Computing | Liu W.,State Key Laboratory of Mathematical Engineering and Advanced Computing | Hu X.,State Key Laboratory of Mathematical Engineering and Advanced Computing
Wireless Personal Communications | Year: 2014

A multi-server authentication scheme enables a remote user to access the services provided by multiple servers after registering with the registration center. Recently, Pippal et al. (Wirel Pers Commun 2013, doi: 10.1007/s11277-013-1039-6) introduced a robust smart card authentication scheme for multi-server architecture. They also illustrated that their scheme could be free from potential network attacks, and validated the scheme by using BAN logic. In this paper, by presenting concrete attacks, we demonstrate that Pippal et al.'s scheme can not withstand off-line password guessing attacks, impersonation attacks and privileged insider attacks. Furthermore, to overcome these attacks, we propose an improved authentication scheme for multi-server architecture using smart card and password. Security and efficiency analysis indicates that our scheme not only actually achieves intended security goals (e.g.; two-factor authentication, perfect forward secrecy etc.), but also is efficient enough to be implemented for practical applications. © 2014 Springer Science+Business Media New York.

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