对两种代理盲签名体制的密码学分析

代理盲签名结合了代理签名与盲签名的优点，而多级代理签名实现了签名权利在许可范围内逐级向下代理的要求。利用椭圆曲线上的双线性对，陈玲玲等人提出了一种基于身份的代理盲签名方案，胡江红等人提出了一种基于身份的多级强代理盲签名方案。给出了这两个方案的密码学分析，指出在陈玲玲等人的方案中，代理签名人可以利用授权证书计算得到原始签名人的私钥，从而可直接伪造原始签名人的签名或授权，同时指出所提的两个方案也无法满足不可追踪性．代理签名人可以将自己在签名协议中的签名和签名的消息联系起来从而跟踪消息的拥有者，从而证明了这两个方案是不安全的。     

用限制性代理盲签名构造多银行电子现金系统

为克服基于群签名思想的多银行电子现金的不足,并提高效率,把盲签名的限制性假设与代理盲签名结合,提出了限制性代理盲签名的概念.根据此概念可构造多个银行参与发行的、公正的电子现金系统.在正常情况下,合法用户的匿名性得到保护,在特殊情况(如法律强制要求)下,发币银行在中央银行的帮助下,可以撤销用户的匿名性.     

代理签字算法在智能卡认证环境中的应用

智能卡可作为理想的密钥存储介质，但由于资源有限，在其内部做公钥运算效率较低。为解决这个问题，结合智能卡的特点，给出了一个基于代理签字算法的安全解决方案。实验表明，与其它方案相比具有高效的特点，同时又能保证卡内密钥信息的安全。     

工业物联网平台的细粒度数据安全技术研究

随着物联网设备的高度普及,智能工厂、智能工业控制系统等工业物联网平台的兴起已成为数字化车间发展的新趋势。尽管制造商广泛关注物联网平台的不同功能要求,但很少考虑安全问题,特别是在数据安全性方面,存在大量隐私泄露的案例。已有一些为工业物联网平台提供安全可靠的通信解决方案,然而,由于在不同的场景中采用了不同的通信协议和交互模型,使得这些解决方案往往是孤立的、碎片化的。因此,为工业物联网平台构建通用的跨平台安全通信技术已成为迫在眉睫的挑战。本文分析不同工业物联网场景的逻辑和要求,并将其抽象为通用模型。针对不同工业物联网平台的可能攻击,设计一种通用的数据安全方案,以条件代理重加密技术为基础来抵御这些攻击。本文提出数据安全技术可确保未经授权的用户无法访问数据。本文还评估了该技术的安全性和性能,实验结果表明,本文的技术方案可以以较低的开销实现高效和安全性要求。     

Using census aggregates to proxy for household characteristics: an application to vehicle ownership

Traditionally, researchers studying transportation choice have used data either acquired from household surveys or broad, region-wide aggregates. At the disaggregate level, researchers usually do not have access to important variables or observations. This study investigates the potential usefulness of a proxy approach to modeling discrete choice vehicle ownership: substituting narrow area-based aggregate proxies for missing micro-level explanatory variables by accessing large, publicly maintained datasets. We use data from the 2000 Bay Area Travel Survey (BATS) and the contemporaneous U.S. Census file to compare three models of vehicle ownership, drawing area-wide proxies from increasing levels of aggregation. The models with proxies are compared with a parallel model that uses only survey data. The results indicate that the proxy models are preferred in terms of model selection criteria, and predict vehicle ownership as well or better than the survey model. Parameter values produced by the proxy method effectively approximate those returned by household survey models in terms of coefficient sign and significance, particularly when the aggregate variables are representative of their household-level counterparts. The proxy model with the narrowest level of aggregation achieved the best fit, coefficient precision, and percentage of correct prediction.

基于椭圆曲线的可控代理签名方案的研究

提出了一种具有限制代理签名者行使代理签名权力的新型可控代理签名方案XECLPS，以解决目前的各种代理签名方案所存在的无法实现对代理签名者的代理签名权力进行全面、完整、可靠地控制的问题．同时对这一方案的复杂性和安全性进行了分析．新方案不仅推广和丰富了代理签名的研究成果和应用范围，而且也扩展了椭圆曲线密码体系的功能，为信息安全同题的解决提供了新的密码学方法．     

Estimation of the determinants of bicycle mode share for the journey to work using census data

A model is presented that relates the proportion of bicycle journeys to work for English and Welsh electoral wards to relevant socio-economic, transport and physical variables. A number of previous studies have exploited existing disaggregate data sets. This study uses UK 2001 census data, is based on a logistic regression model and provides complementary evidence based on aggregate data for the determinants of cycle choice. It suggests a saturation level for bicycle use of 43%. Smaller proportions cycle in wards with more females and higher car ownership. The physical condition of the highway, rainfall and temperature each have an effect on the proportion that cycles to work, but the most significant physical variable is hilliness. The proportion of bicycle route that is off-road is shown to be significant, although it displays a low elasticity (+0.049) and this contrasts with more significant changes usually forecast by models constructed from stated preference based data. Forecasting shows the trend in car ownership has a significant effect on cycle use and offsets the positive effect of the provision of off-road routes for cycle traffic but only in districts that are moderately hilly or hilly. The provision of infrastructure alone appears insufficient to engender higher levels of cycling.

On constructing certificateless proxy signature from certificateless signature

In proxy signature schemes, an original signer A delegates its signing capability to a proxy signer B, in such a way that B can sign message on behalf of A.The recipient of the final message verifies at the same time that B computes the signature and that A has delegated its signing capability to B.Recently many identity-based(ID-based) proxy signature schemes have been proposed, however, the problem of key escrow is inherent in this setting.Certificateless cryptography can overcome the key escrow problem.In this paper, we present a general security model for certificateless proxy signature scheme.Then, we give a method to construct a secure certificateless proxy scheme from a secure certificateless signature scheme, and prove that the security of the construction can be reduced to the security of the original certificateless signature scheme.