一种面向密码芯片的旁路攻击防御方法

针对不同级别的旁路信息泄露,提出一种通用的旁路信息泄露容忍防御模型,并结合信息熵理论给出该模型的形式化描述.该模型采用(t,n)门限机制,使得部分旁路信息泄露不会影响系统的安全性.在该防御模型的基础上,结合高级加密标准AES-128算法的安全实现,设计了一种两阶段掩码的旁路攻击防御方法.与已有的防御方法相比,该方法能够同时防御高阶旁路攻击与模板攻击.通过理论分析与仿真实验验证了该方法的有效性.     

基于路径损耗的无线传感器网络分布式拓扑控制算法

对无线传感器网络中目前最常用的3种链路度量标准进行分析和比较得出,在满足一定收包率要求时,节点的接收信号强度存在一个最小阈值.考虑接收信号强度作为拓扑构建条件时需节点具备相同发射功率的不足,提出将路径损耗大小作为拓扑构建的条件,设计了一种分布式拓扑控制算法——PLBD.该算法在保证收包率的同时,还使各节点之间的通信保留最小损耗链路.仿真结果表明,PLBD算法构建的拓扑不仅能够保证网络连通性,还具有通信时延低,健壮性好,能量消耗相对均衡的特点.     

The Holy Alignment: Geodesic and Astronomical Fundamentals for Calculating the Adjustment of Medieval Naves

It is commonly believed that the longitudinal axes of churches extend exactly in an east-west direction. However, thorough investigations have shown that this is not always correct; rather, both southern and northern deviations of up to about 25° can occur. The angular deviation between the church axis and true east is called the Holy Alignment. This present study presents the possibility that the nave is oriented towards the direction of the sun-rising point on the name day of the patron saint of the church. If several saints share the patronage, the Holy Alignment equals the algebraic sum of the angular distances for each saint. The orientation of a nave can be analyzed by means of common mathematical relations used in geodesy, astronomy and gnomonics. In order to perform such an analysis, it is necessary to know the history of the patronage of the church; the Gauss-Krüger coordinates of the ground plan; and characteristic astronomical quantities at the time the church was built. A calculated example with the saints Andrew, James and Philip for the year 980 illustrates the analysis. An appendix deals with the influence of atmospheric refraction on the apparent altitude of the sun near the horizon.     

Efficient identity-based GQ multisignatures

ISO/IEC 14888 specifies a variety of digital signature mechanisms to sign messages of arbitrary length. These schemes can be applied to provide entity authentication, data origin authentication, non-repudiation, and data integrity verification. ISO/IEC 14888 consists of three parts under the general title Information technology—Security techniques—Digital signatures. Part II, or ISO/IEC 14888-2 specifies the general structure and the fundamental procedures for the generation and verification of an identity-based signature (IBS) mechanism for messages of arbitrary length. Particularly, the IBS scheme of Guillou and Quisquater (GQ) is described in Clauses 6–8. In this paper, an efficient identity-based multisignature (IBMS) scheme is proposed for the GQ IBS scheme, which allows multiple users using the ISO/IEC 14888-2 standard GQ scheme to generate multisignatures. The scheme is efficient in the sense that both the length and the verification time of the multisignatures are fixed. The proposed ID-based multisignature scheme is also secure against forgeability under adaptive chosen-message attack and adaptive chosen-identity attack in random oracle model.     

如何设定品牌标志的设计标准

品牌设计师通过知觉联想可以将文字语言转化为直接、可见的视觉图形传达给社会大众,这种语言上的转换是设计师发掘人们想象不到或想象不全面的一种表现方式,是艺术创造。同时,在没有限制,具有广泛可能性的创意、设计中,要把企业理念和目标等文字语言浓缩、整合出适合创意、设计的关键语,这一个个关键语就是品牌标志设计的依据和标准。有了这样的设计标准就会提高设计效率和准确性,减少在标志设计过程中的矛盾与摩擦,起到指引方向和检验最终方案的作用。     

构件化信息系统开发方法研究

首先由传统的信息系统开发方式的缺陷引出了软件构件化概念,然后对构件的属性、构件开发标准规范、信息系统构件化开发方法进行了介绍,最后给出了一种信息系统构件化开发框架探讨信息系统的构件化开发方法。     

抗DPA攻击的AES算法研究与实现

Mask技术破坏了加密过程中的功率消耗与加密的中间变量之间的相关性,提高了加密器件的抗DPA攻击能力。简单地对算法流程添加Mask容易受到高阶DPA攻击的。提出了一种对AES加密过程的各个操作采用多组随机Mask进行屏蔽的方法,并在8bit的MCU上实现了该抗攻击的AES算法。实验结果表明,添加Mask后的抗DPA攻击AES算法能够有效地抵御DPA和高阶DPA的攻击。     

一种基于H.264/AVC的快速帧间模式选择算法

为了解决帧间模式选择计算量大的问题,提出了一种快速算法。算法利用编码模式的利用率信息和时空相关性来预先判定当前宏块最可能的编码模式,从而大大加快了模式选择的过程。算法缩小了候选模式的范围,并采用阈值来提高预测准确度。仿真结果表明,该算法在编码质量只有轻微下降的情况下明显降低了计算复杂度。     

堤防工程设计防洪标准探讨

就＜＜堤防工程技术规范＞＞和＜＜堤防工程设计规范＞＞编制过程中的体会,笔者认为,许多部门的防护对象都有各自的防洪标准,但在堤防工程设计时,防洪标准需要统一、防护区的划分是确定堤防工程防洪标准的基础工作,需要有一套完整的计算方法;防洪标准中的防护对象不可能包罗万象,标准的拟定和运用,都有防护对象分类和类比的问题,影响堤防工程等级的因素很多,单纯用防护对象的防洪要求作为指标是片面的,国内外表达防护对象