基于认证测试的安全协议分析

认证测试是一种新型的在Strand空间模型基础上发展而来的安全协议分析与辅助设计技术,可用于大部分协议的关联属性的分析;但是与Strand空间模型一样,它主要用于协议正确性证明,在协议为何不正确以及如何进行改进这个问题上处理分析能力较弱.在认证测试概念的基础上,结合逻辑分析的优点,提出了增强型认证测试EAT(enhanced authentication test)和Correspondence函数等概念来对安全协议进行关联属性的分析,很好地解决了这一问题与原有技术相比,该方法更为形式化,协议分析人员可以很方便地进行手动分析,并且更有利于协议分析自动化工具的实现.     

Computer modelling and finite element analysis of spiral triangular strands

In this paper a new mathematical geometric model of spiral triangular wire strands with a construction of (3 + 9) and (3 + 9 + 15) wires is proposed and an accurate computational two-layered triangular strand 3D solid modelling, which is used for a finite element analysis, is presented. The present geometric model fully considers the spatial configuration of individual wires in the strand. The three dimensional curve geometry of wires axes in the individual layers of the triangular strand consists of straight linear and helical segments. The derived mathematical representation of this curve is in the form of parametric equations with variable input parameters which facilitate the determination of the centreline of an arbitrary circular wire of the right and left hand lay triangular one and two-layered strands. Derived geometric equations were used for the generation of accurate 3D geometric and computational strand models. The correctness of the derived parametric equations and performance of the generated strand model are controlled by visualizations. The 3D computational model was used for a finite element behaviour analysis of the two-layered triangular strand subjected to tension loadings. Illustrative examples are presented to highlight the benefits of the proposed geometric parametric equations and computational modelling procedures by using the finite element method.     

Compression moulding of Carbon/PEEK Randomly-Oriented Strands composites: A 2D Finite Element model to predict the squeeze flow behaviour

Compression moulding of Randomly-Oriented Strands (ROS) of pre-impregnated thermoplastic composites is a process that enables the forming of complex parts with features such as ribs, thickness variations and holes in one single moulding step. This paper focuses on the macroscopic squeeze flow behaviour that occurs during forming. This mechanism rules the filling of intricate features of the mould initially empty. A 2D Finite Element model was developed to predict the squeeze flow of ROS composites. The material was modelled as a Bingham fluid and the equivalent viscosity and yield stress of three different strand sizes were determined using an inverse method. The viscosity and yield stress were found to increase with strand length. Experimental validation of the model was performed using Carbon/PEEK ROS flat samples and the average difference between experimentally measured and predicted final strain was below 5% for all cases.     

信达金融大厦无粘结预应力墙梁的设计与施工

信达金融大厦外墙自５ 层以上采用无粘结预应力混凝土刚性墙梁,结构形式特殊。本文介绍大跨度无粘结预应力梁的设计、施工难点,张拉、测试等,并根据测试结果进行了分析和探讨。     

顶推梁设计、施工中有关张拉、压浆问题的分析与处理——兼介一种新型钢绞线联接器

总结多座顶推梁预应力张拉和压浆的基础上,对有关问题的分析与处理进行了详细介绍。同时介绍了一种新型钢绞线联接器。     

加速预应力钢丝钢绞线用盘条的国产化进程

介绍预应力结构用钢丝和钢绞线的国产化现状 ,分析了国产盘条与国外产品的主要差距 ,从炼钢、浇铸、轧制、热处理、表面保护等方面提出了改进措施。也介绍了镀锌预应力钢丝的特殊质量要求。对盘条生产国产化提出了见解。     

ISI支付协议的Strand Space模型及其公平性分析

文章利用StrandSpace模型对ISI支付协议进行了分析,得出了与卿_周逻辑分析方法相同的结论,并将StrandSpace模型对认证协议协定性的分析方法应用到了电子商务协议公平性的分析。     

基于串空间模型的Andrew安全RPC协议分析

在Andrew安全RPC协议模型的基础上,运用安全协议的形式化串空间模型分析方法,对Andrew安全RPC协议进行了分析,说明了该方法进行协议分析的过程,证明了该协议在机密性和认证性方面的正确性,并分析了该协议存在的安全缺陷。     

一种新的安全协议及其串空间模型分析

针对有限域上计算离散对数的困难,提出了一种新的身份认证与密钥协商安全协议——PJY。PJY安全协议通过两次握手就可以验证通信双方的身份,同时产生对等的会话密钥。采用串空间模型分析该安全协议的正确性,通过构造渗透串空间模型,采用认证测试证明了PJY安全协议在任意一种攻击串模式下都具有单射一致性和机密性,从而证明了PJY安全协议的正确性。