Property of finite fields and its cryptography application

A new property of finite fields is discovered, that the co-ordinates of the finite field element are expressed by algebraic polynomials with the element itself as the variable. The new property is used to determine the algebraic expression of the Rijndael S box. Furthermore, it is shown why the expression of the Rijndael S box appears so simple.     

描述Rijndael的一个新的方程组

由于Rijndael的S盒的代数表达式是逆函数合成GF(28)上一个q-多项式,该文合理假设S盒的变量并通过讨论各变量之间的关系,把Rijndael用GF(28)上一个多变量二次方程组来表示,使得Rijndael的密钥恢复等同于求解这个方程组.该方程组较Murphy-Robshaw方程组更简单,用XSL技术求解复杂度更低。     

Rijndael算法的代数方程系统改进

该文根据Rijndael算法中S盒的代数表达式,通过合理假设S盒变量,利用各变量之间的关系建立方程,把Rijndael加密算法描述成GF(28)上的一个多变量二次方程系统。该二次方程系统是稀疏的且是超定(Overdefined)的,可以认为恢复Rijndael的密钥等同于求解这个方程系统。与其他描述Rijndael密码的方程系统相比,该文中描述S盒方程的项数与变量更少,因此用XSL(eXtended Sparse Linearization)技术求解该系统的计算复杂度更低。     

Rijndael算法的硬件实现

提出了Rijndael的硬件实现的算法,它是128位对称分组加密的高级加密标准。设计目标是FPGA实现。系统由AddroundKey、ShiftRows、Mixcolumns和s盒四个部分组成。因为Rijndael算法需要大量硬件资源,每一个部分除了S盒外都只实现了一次,并工作在非反馈模式下。该设计在MAX+PLUSIIFPGA工具中进行了仿真。     

域元素分量代数表达式的研究

本文提出了有限域上的一个新性质:用变元为域元素的多项式表示域元素的分量.基于等价类的划分、线性方程组的求解和标准基之对偶基的计算,提出了域元素分量代数表达式的三种求法.以此解释了Rijndael算法S盒代数表达式复杂度低的本质原因,给出其分量函数间等价关系的一种直接证明方法.     

A class of 1-generator quasi-cyclic codes

If R = F/sub q/[x/spl rceil/]/(x/sup m/ - 1), S = F/sub qn/[x]/(x/sup m/ - 1), we define the mapping a_(x) /spl rarr/ A(x) =/spl sigma//sub 0//sup n-1/a/sub i/(x)/spl alpha//sub i/ from R/sup n/ onto S, where (/spl alpha//sub 0/, /spl alpha//sub i/,..., /spl alpha//sub n-1/) is a basis for F/sub qn/ over F/sub q/. This carries the q-ray 1-generator quasicyclic (QC) code R a_(x) onto the code RA(x) in S whose parity-check polynomial (p.c.p.) is defined as the monic polynomial h(x) over F/sub q/ of least degree such that h(x)A(x) = 0. In the special case, where gcd(q, m) = 1 and where the prime factorizations of x/sub m/ 1 over F/sub q/ and F/sub qn/ are the same we show that there exists a one-to-one correspondence between the q-ary 1-generator quasis-cyclic codes with p.c.p. h(x) and the elements of the factor group J* /I* where J is the ideal in S with p.c.p. h(x) and I the corresponding quantity in R. We then describe an algorithm for generating the elements of J*/I*. Next, we show that if we choose a normal basis for F/sub qn/ over F/sub q/, then we can modify the aforementioned algorithm to eliminate a certain number of equivalent codes, thereby rending the algorithm more attractive from a computational point of view. Finally in Section IV, we show how to modify the above algorithm in order to generate all the binary self-dual 1-generator QC codes.     

A Decomposition Method for Computing System Reliability by a Boolean Expression

A substitutionary decomposition method for computing the reliability of a redundant system S given by a Boolean expression is proposed, System S is decomposed into two subsystems S(x) and S(x?) according to up-and down-states of its keystone variable x. This is repeated until all terms become s-independent in each decomposed subsystem. A criterion for choosing the keystone variable and a property which saves computation time are obtained.     

Rijndael FPGA Implementations Utilising Look-Up Tables

This paper presents single-chip FPGA Rijndael algorithm implementations of the Advanced Encryption Standard (AES) algorithm, Rijndael. In particular, the designs utilise look-up tables to implement the entire Rijndael Round function. A comparison is provided between these designs and similar existing implementations. Hardware implementations of encryption algorithms prove much faster than equivalent software implementations and since there is a need to perform encryption on data in real time, speed is very important. In particular, Field Programmable Gate Arrays (FPGAs) are well suited to encryption implementations due to their flexibility and an architecture, which can be exploited to accommodate typical encryption transformations. In this paper, a Look-Up Table (LUT) methodology is introduced where complex and slow operations are replaced by simple LUTs. A LUT-based fully pipelined Rijndael implementation is described which has a pre-placement performance of 12 Gbits/sec, which is a factor 1.2 times faster than an alternative design in which look-up tables are utilised to implement only one of the Round function transformations, and 6 times faster than other previous single-chip implementations. Iterative Rijndael implementations based on the Look-Up-Table design approach are also discussed and prove faster than typical iterative implementations.     

(Mg_(1–x)Zn_x)TiO_3系陶瓷微波介电性能的研究

以MgCO3、ZnO和TiO2为原料,用固相反应法制备了(Mg1–xZnx)TiO3(MZT)系陶瓷。研究了ZnO含量对其微观结构和微波介电性能的影响。结果表明:添加适量ZnO,可有效降低烧结温度,拓宽烧结温度范围。当x(ZnO)为30%,烧结温度为1250℃时,MZT陶瓷具有优良微波介电性能,εr为16～18,Q·f为90000GHz,τc为–5.1×10–7℃–1。     

AES算法的密码分析与快速实现

高级加密标准(AES)确定分组密码Rijndael为其算法,取代厂泛使用了20多年的数据加密标准(DES),该算法将在各行业各部门获得广泛的应用.文章以DES为参照对象,阐述了Rijndael算法的设计特色,介绍了AES在密码分析方面国内外已有的一些理论分析成果,描述了AES算法采用软件和硬件的快速实现方案.     

Mg-Al-Cr-Fe系高温NTC陶瓷材料的改性研究

采用传统陶瓷方法制作了Mg1+xAl0.8Cr0.6Fe0.6Lay(x=–0.10,–0.05,0,0.05,0.10,0.15,0.20;y=0,0.05)系高温NTC陶瓷材料,借用XRD、SEM和电性能测试等手段,研究了MgO含量及La2O3掺杂对陶瓷材料相结构和电学性能的影响规律。结果表明:适当增加MgO的含量可以有效提高陶瓷材料的常温电阻率和B值(材料常数),La2O3掺杂可改善高温NTC陶瓷材料B值的稳定性。当x=0.15,y=0.05时,在1 873 K烧结可获得ρ25=7.55×1010.cm,B=8 795 K的高温NTC陶瓷材料。     

核泵浦~3He-Ne激光增益实验

在稳态核反应堆上,测定了热中子辐照下,~3He-Ne激光体系(P_(He:P_(Ne)=5:1,P_总=4×10~4Pa)的增益系数(丸=632.8nm,跃迁3S_2-2P_4)。当热中子通量为2×10~(12)n/cm~2·时,其增益系数为1.7×10~(-2)/cm。研究了增益系数随热中子通量的变化关系,讨论了温度对增益的影响。实验表明核泵浦~3He-Ne体系有可能实现激射。     

基于AES算法的WLAN安全机制分析

高级加密标准(AES)加密算法Rijndael采用对称的块加密技术,提供比WEP/TKIP中RC4算法更高的加密性能,它将成为取代WEP的新一代的加密技术,为无线网络带来更强大的安全防护.文章主要讲述了AES加密算法,在分支编码本(OCB)模式下的AES加密机制原理,AES算法在WLAN中的应用,以及现有的一些针对AES算法的攻击方法.     

AES算法Rijndael的原理、实现和攻击

分组密码Rijndael算法是美国21世纪高级加密标准AES,用于保护联邦政府敏感非机密信息,任何组织、机构和个人可自愿使用。这里详细介绍了它的设计原理、实现方法和目前存在的攻击方法,并指出破译分析的方法原则。     

Rijndael扩展算法及其JAVA实现

探讨了长度大于256比特明文和密钥的Rijndael密码扩展算法，分析了扩展Rijndael算法的输入明文和密钥的排列规则和随后轮处理中各个步骤采用的处理方法，提出了一种通过Ri-jndael算法自身加密密钥来增强扩展密钥安全性的方法，介绍了Rijndael算法的JAVA软件实现和其核心模块的JAVA编程。     

新型Sb掺杂SnO_2基NTC热敏材料的研制

为了提高SnO2基NTC热敏材料的电学性能稳定性,采用共沉淀法合成了Sb掺杂SnO2材料,[Sn1-xSbxO2+δ(x=0.02,0.04,0.05和0.07)]。利用XRD对其进行了相分析,利用电阻–温度特性测试仪研究其电阻温度特性。结果表明:500℃煅烧后获得了具有高纯四方相、晶粒尺寸小于10nm的Sb掺杂SnO2材料;x(Sb)为2%、4%、5%和7%的热敏电阻的材料常数B分别为6616,6207,5730和2197K。     

生长于Pt/Ti/SiO2/Si衬底的ZnxNi(1-x)Mn2O4薄膜的结构与光学性质

采用化学溶液法在Pt/Ti/SiO2/Si衬底上生长了ZnxNi1-xMn2O4（ZNMO, x=0, 0.05, 0.1, 0.15, 0.2, 0.25）尖晶石氧化物薄膜。X射线衍射(XRD) 与场发射扫描电子显微镜(FESEM) 分析结果表明,Zn的掺杂浓度对ZNMO薄膜的结晶性和微结构有明显影响。用椭圆偏振光谱仪测量分析了ZNMO薄膜在300-1100nm波段的光学常数,并讨论了Zn掺杂对折射率n和消光系数k的影响。在薄膜的拉曼光谱中观测到两个峰A1g与F2g,A1g模式的相对峰位随着Zn的掺杂浓度x的增大而减小。由于晶格应变与晶格失配,拉曼峰峰位随Zn掺杂浓度的变化而轻微移动。     

Impact of local oscillator intensity noise on performance of coherent subcarrier multiplexing system using common local oscillator (CLO)

The impact of local oscillator intensity noise on the performance of a coherent subcarrier multiplexing (CSCM) system using a common local oscillator (CLO) is analysed. For a given LO power, RIN noise, and thermal noise, the CNR can be expressed in terms of x, the ratio of sigma /sub sh//sup 2/+ sigma /sub th//sup 2/ over sigma /sub RIN//sup 2/ and, for x<<1, the CNR decreases as LO power increases; for x>>1, the CNR increases as the LO power increases; as x approaches 1, there exist an optimum value of local oscillator power and a corresponding maximum CNR. For a system with RIN=-150 dB/Hz, P/sub S/=-20 dBm, beta =0.02, N=40, NF=3 dB and B=10 MHz, the (P/sub LO/)/sub opt/ is found to be -4 dBm and (CNR)/sub max/ 22.5 dB.<>     

密钥控制的多S盒Rijndael算法

根据AESS盒的设计思想构造出了一批密码性能良好的S盒,并从方差的角度对它们的雪崩概率进行了分析。在此基础上,对Rijndael算法中的字节代换步骤SubBytes进行改进,从而提出了一种基于密钥控制的多S盒的Rijndael算法。实验结果表明,改进后的算法对差分攻击的抵抗能力有所提高,雪崩效应更趋合理。     

添加MnO2对ZnO-B2O3-P2O5-RnOm玻璃性能的影响

在ZnO-B<,2>O<,3>-P<,2>O<,5>-R<,n>O<,m>(R=Na、Al、Li)系玻璃中掺杂摩尔分数1%～5%的MnO<,2>,分析了MnO<,2>掺杂对玻璃的耐水性和流散性的影响,通过XRD分析了晶相的变化,通过摄像照片观察了玻璃试样受水侵蚀后表面形貌的变化.结果表明:当x(MnO<,2>)=3%时...