Shuffled frog leaping algorithm and its application to 0/1 knapsack problem

This paper proposes a modified discrete shuffled frog leaping algorithm (MDSFL) to solve 01 knapsack problems. The proposed algorithm includes two important operations: the local search of the ‘particle swarm optimization’ technique; and the competitiveness mixing of information of the ‘shuffled complex evolution’ technique. Different types of knapsack problem instances are generated to test the convergence property of MDSFLA and the result shows that it is very effective in solving small to medium sized knapsack problems. Further, computational experiments with a set of large-scale instances show that MDSFL can be an efficient alternative for solving tightly constrained 01 knapsack problems.     

对基于离散对数的分布式加密算法的攻击

组播为组通信提供一个可扩展的解决方案,而组密钥管理是安全组通信最重要的组成部分。Chaddoud和Varadharajan在安全特定源组播体系结构中利用Yi,Varadharajan和Zhao的分布式公钥加密算法提出了一种信道密钥管理方案。我们首先论证在该算法中使用强的单向散列函数不仅是不必要的,而且还诱发敌手利用剩余类环中的零因子对其发起一种被动攻击,从而表明原算法及原方案是不安全的。其次通过重新配置系统参数,改进后的加密算法既能提高抵抗零因子攻击的能力,又能保持密码学意义上的理想语意特性。     

Feedback shift registers, 2-adic span, and combiners with memory

Feedback shift registers with carry operation (FCSRs) are described, implemented, and analyzed with respect to memory requirements, initial loading, period, and distributional properties of their output sequences. Many parallels with the theory of linear feedback shift registers (LFSRs) are presented, including a synthesis algorithm (analogous to the Berlekamp-Massey algorithm for LFSRs) which, for any pseudorandom sequence, constructs the smallest FCSR which will generate the sequence. These techniques are used to attack the summation cipher. This analysis gives a unified approach to the study of pseudorandom sequences, arithmetic codes, combiners with memory, and the Marsaglia-Zaman random number generator. Possible variations on the FCSR architecture are indicated at the end. Andrew Klapper was sponsored by the Natural Sciences and Engineering Research Council under Operating Grant OGP0121648, the National Security Agency under Grant Number MDA904-91-H-0012, and the National Science Foundation under Grant Number NCR9400762. The United States Government is authorized to reproduce and distribute reprints notwithstanding any copyright notation hereon. Mark Goresky was partially supported by the Ellentuck Fund and National Science Foundation Grant Number DMS 9304580.     

用组合网络构造分组密码

本文提出了组合网络的概念,将此网络的输入、输出关系作加密变换,构造了一个秘密密钥分组密码,分析了其安全性。     

异步保密机中密码滚动探讨

用数论变换实现的异步保密机中，再采用密码滚动，提高密钥量和通信的可靠性。在密钥滚动、同步建立、帧失步修正等方面作了尝试性的工作。     

扩散码及其密码学用途

本文提出了单比特和多比特扩散码以及用它们构造认证码和分组密码的方法。这些密码学函数可以用快速且类型单纯的操作指令来实现，迭代轮数少，且有好的安全性，用软件硬件均容易实现。     

A fast correlation attack on LILI-128

In this paper we demonstrate a fast correlation attack on the recently proposed stream cipher LILI-128. The attack has complexity around 2⁷¹ bit operations assuming a received sequence of length around 2³⁰ bits and a precomputation phase of complexity 2⁷⁹ table lookups. This complexity is significantly lower than 2¹¹², which was conjectured by the inventors of LILI-128 to be a lower bound on the complexity of any attack.     

Cisco常见路由器密码和版本恢复方法探讨

本文对CLSCO公司的一些常见路由器的密码恢复进行了探讨和总结，同时描述了对路由器版本的灾难性恢复的一些方法。     

A weak cipher that generates the symmetric group

There has been recent interest in the permutation group generated by the round functions of a block cipher. In this paper we present a cautionary example of a block cipher which generates the full symmetric group yet is very weak.     

混沌序列产生方法及其在图象加密中的应用

介绍了一个混沌二值序列产生和实验的软件平台，它利用三种混沌动力学模型，即一阶时延模型、Lorenz模型、Logistic模型产生加密序列，并通过大量实验对产生的序列的伪随机性、敏感性、重复性进行了测试，测试表明混沌伪随机序列具有良好的加密性能。本系统还可以提供对多种对象的加／解密实验和分析，同时也给出了对．bmp格式图像加／解密的实验结果。