In order to improve the attack efficiency of the New FORK-256 function, an algorithm based on Grover's quantum search algorithm and birthday attack is proposed. In this algorithm, finding a collision for arbitrary...In order to improve the attack efficiency of the New FORK-256 function, an algorithm based on Grover's quantum search algorithm and birthday attack is proposed. In this algorithm, finding a collision for arbitrary hash function only needs O(2m/3) expected evaluations, where m is the size of hash space value. It is proved that the algorithm can obviously improve the attack efficiency for only needing O(2 74.7) expected evaluations, and this is more efficient than any known classical algorithm, and the consumed space of the algorithm equals the evaluation.展开更多
This study sets up two new merit functions,which are minimized for the detection of real eigenvalue and complex eigenvalue to address nonlinear eigenvalue problems.For each eigen-parameter the vector variable is solve...This study sets up two new merit functions,which are minimized for the detection of real eigenvalue and complex eigenvalue to address nonlinear eigenvalue problems.For each eigen-parameter the vector variable is solved from a nonhomogeneous linear system obtained by reducing the number of eigen-equation one less,where one of the nonzero components of the eigenvector is normalized to the unit and moves the column containing that component to the right-hand side as a nonzero input vector.1D and 2D golden section search algorithms are employed to minimize the merit functions to locate real and complex eigenvalues.Simultaneously,the real and complex eigenvectors can be computed very accurately.A simpler approach to the nonlinear eigenvalue problems is proposed,which implements a normalization condition for the uniqueness of the eigenvector into the eigenequation directly.The real eigenvalues can be computed by the fictitious time integration method(FTIM),which saves computational costs compared to the one-dimensional golden section search algorithm(1D GSSA).The simpler method is also combined with the Newton iterationmethod,which is convergent very fast.All the proposed methods are easily programmed to compute the eigenvalue and eigenvector with high accuracy and efficiency.展开更多
针对结构化P2P(Peer to Peer)网络资源高效搜索问题,提出了一种基于新路由表的双向搜索chord路由算法。该算法为解决chord算法路由表中存在着大量冗余信息,查找资源效率低下等缺点,提出了一个新的路由表构造公式。该公式首次加入路由因...针对结构化P2P(Peer to Peer)网络资源高效搜索问题,提出了一种基于新路由表的双向搜索chord路由算法。该算法为解决chord算法路由表中存在着大量冗余信息,查找资源效率低下等缺点,提出了一个新的路由表构造公式。该公式首次加入路由因子概念,充分考虑了网络中节点个数和资源个数对路由表的影响,在不增加路由表项的前提下,不仅基本删除了路由表的冗余项,还实现了chord环的双向查找以减少平均查找跳数。实验仿真结果表明,该算法基本消除了路由表中的冗余信息,减少了平均查找跳数,有效地提高了资源的查找效率。展开更多
基金Supported by the National High Technology Research and Development Program(No.2011AA010803)the National Natural Science Foundation of China(No.U1204602)
文摘In order to improve the attack efficiency of the New FORK-256 function, an algorithm based on Grover's quantum search algorithm and birthday attack is proposed. In this algorithm, finding a collision for arbitrary hash function only needs O(2m/3) expected evaluations, where m is the size of hash space value. It is proved that the algorithm can obviously improve the attack efficiency for only needing O(2 74.7) expected evaluations, and this is more efficient than any known classical algorithm, and the consumed space of the algorithm equals the evaluation.
基金the National Science and Tech-nology Council,Taiwan for their financial support(Grant Number NSTC 111-2221-E-019-048).
文摘This study sets up two new merit functions,which are minimized for the detection of real eigenvalue and complex eigenvalue to address nonlinear eigenvalue problems.For each eigen-parameter the vector variable is solved from a nonhomogeneous linear system obtained by reducing the number of eigen-equation one less,where one of the nonzero components of the eigenvector is normalized to the unit and moves the column containing that component to the right-hand side as a nonzero input vector.1D and 2D golden section search algorithms are employed to minimize the merit functions to locate real and complex eigenvalues.Simultaneously,the real and complex eigenvectors can be computed very accurately.A simpler approach to the nonlinear eigenvalue problems is proposed,which implements a normalization condition for the uniqueness of the eigenvector into the eigenequation directly.The real eigenvalues can be computed by the fictitious time integration method(FTIM),which saves computational costs compared to the one-dimensional golden section search algorithm(1D GSSA).The simpler method is also combined with the Newton iterationmethod,which is convergent very fast.All the proposed methods are easily programmed to compute the eigenvalue and eigenvector with high accuracy and efficiency.
文摘针对结构化P2P(Peer to Peer)网络资源高效搜索问题,提出了一种基于新路由表的双向搜索chord路由算法。该算法为解决chord算法路由表中存在着大量冗余信息,查找资源效率低下等缺点,提出了一个新的路由表构造公式。该公式首次加入路由因子概念,充分考虑了网络中节点个数和资源个数对路由表的影响,在不增加路由表项的前提下,不仅基本删除了路由表的冗余项,还实现了chord环的双向查找以减少平均查找跳数。实验仿真结果表明,该算法基本消除了路由表中的冗余信息,减少了平均查找跳数,有效地提高了资源的查找效率。
