Algebraic properties of cryptosystem PGM

In the late 1970s Magliveras invented a private-key cryptographic system calledPermutation Group Mappings (PGM). PGM is based on the prolific existence of certain kinds of factorization sets, calledlogarithmic signatures, for finite permutation groups. PGM is an endomorphic system with message space ℤ_|G| for a given finite permutation groupG. In this paper we prove several algebraic properties of PGM. We show that the set of PGM transformations ℐ _G is not closed under functional composition and hence not a group. This set is 2-transitive on ℤ_|G| if the underlying groupG is not hamiltonian and not abelian. Moreover, if the order ofG is not a power of 2, then the set of transformations contains an odd permutation. An important consequence of these results is that the group generated by the set of transformations is nearly always the symmetric group ℒ_|G|. Thus, allowing multiple encryption, any permutation of the message space is attainable. This property is one of the strongest security conditions that can be offered by a private-key encryption system. S. S. Magliveras was supported in part by NSF/NSA Grant Number MDA904-82-H0001, by U.S. West Communications, and by the Center for Communication and Information Science of the University of Nebraska.     

VLCC中的DAG并行算法

基于组件的密码学虚拟实验室（VLCC）采用有向无环图（DAG）的拓扑排序机制管理组件。在分析VLCC各组件之间的数据依赖和运行次序关系的基础上,提出一种新的基于Java多线程机制和“唤醒”机制的DAG并行算法。与拓扑排序算法相比,具有低算法时间复杂度的特点。实验结果表明,系统在新算法下较大地缩短了系统运行时间,提高资源使用效率和用户满意度,能更好地完善VLCC。     

网络攻击与安全防护的分类研究

根据网络安全的研究与实现层面,提出了把网络攻击分为密码学意义上的理论攻击和现实意义上的技术攻击,对网络安全防护技术也做了类似划分,在此基础上对当前各类网络攻击和安全保护技术做了详尽的归类,并指出未来网络安全保护需注意的重点问题和可能的发展趋势。     

THE ADVENT OF CRYPTOLOGY IN THE GAME OF BRIDGE

The surprising discovery that information can be passed both covertly and legally between bridge partners has added a new dimension to the theory of this popular game. In this paper some of the methods are sketched and their cryptologic foundation is described.     

一种网络支付手段—电子现金

本文首先介绍了一种网络支持手段－电子现金的性质，然后简要描述了电子现金系统，最后着重分析了支付中应考虑的主要问题及解决方案。     

Shannon信息保密理论的新进展

本文介绍Ｓｈａｎｎｏｎ信息保密理论若干新进展。     

The public cryptography study group

The Public Cryptography Study Group was created by the American Council on Education in the spring of 1980 to examine concerns expressed by the Director of NSA caused by the rapid growth of interest in cryptology as a means for the protection of data files. Written by a participant in the study, this paper discusses many of the issues that came before the committee, including the danger to security systems produced by inadvertent or malicious disclosure of weak points in the system which would render it ineffective. It concludes by summarizing the recommendations in the final report of the PCSG, and describes the implementation of the voluntary review procedure recently announced by the Director of NSA. The procedures are designed to decrease the danger to public, private and governmental national security, without impeding the growth of nongovernmental research.     

序列的周期稳定性的新度量指标

本文提出了两种新的度量序列的周期稳定性的指标－定周期距离和变周期距离。文中还研究了一些序列的这两种指标的下界，并给出了衡量序列的周期稳定性的一种方法。     

A design of a fast pipelined modular multiplier based on a diminished-radix algorithm

We present a new serial-parallel concurrent modular-multiplication algorithm and architecture suitable for standard RSA encryption. In the new scheme, multiplication is performed modulo a multiple of the RSA modulus n, which has a diminished-radix form 2 ^k -v, where k and v are positive integers and v < n. This design is the first concurrent modular multiplier to use a diminished-radix algorithm and to pipeline concurrent modular-reduction to optimize the clock rate. For a modular multiplier of order ranging from 1 to 10 (number of multiplier bits per clock cycle), a faster clock rate and throughput is possible than with other known designs including those of Brickell, Morita, Sedlak and Golze, and Miyaguchi. Throughput estimates for 512-bit RSA decryption range from 100 kbit/s in a serial mode to 650 kbit/s with a modular multiplier of order 10, at a clock rate of 20 MHz on 1.5 m CMOS.     

THE HAND-HELD CALCULATOR AS A CRYPTOGRAPHIC MACHINE

The degree of sophistication available in today's programmable personal calculators may be used to provide a practical field cipher capability of significant power. Procedures are presented for key management, key generator cycling alarm, cipher-type selection to match cryptanalytic threat level, and key length options as an answer to key-search attacks. Three basic cipher procedures are presented with special emphasis given to the inherent power of transposition techniques. Four cryptogram examples are included to demonstrate four of the levels of available security offered by the system.