有指定秘书的(t,n)门限群签名体制

设计了一类只有指定的秘书才能发布有效群签名的可追查签名者身份的(t,n)门限群签名体制．该体制的优点是：(1)验证的简单性;(2)系统更新时无须更改每个成员的子密钥;(3)成员的增加或删除不影响群中其他的成员;(4)群中成员的子密钥可以无限制的使用;(5)t个成员合谋无法假冒其他成员生成有效的群签名．     

基于MSP秘密共享的（t，n）门限群签名方案

门限群签名是群签名中重要的—类,它是秘钥共享与群签名的有机结合．本文通过文献[5]中的MSP方案（Monotone Span Program）,提出了一种新的门限群签名方案．在本签名方案建立后,只有达到门限的群成员的联合才能生成—个有效的群签名,并且可以方便的加入或删除成员．一旦发生争议,只有群管理员才能确定签名人的身份．该方案能够抵抗合谋攻击：即群中任意一组成员合谋都无法恢复群秘钥k．本方案的安全性基于Gap Diffie-Hellman群上的计算Diffie-Hellmanl可题难解上,因此在计算上是最安全的．     

一种基于矩阵法秘密分享协议的门限数字签名方案

本文研究了门限数字签名.根据一种矩阵法町验证秘密分享协议,构造出一种新的有指定接收者的、基于椭圆曲线密码机制(ECC)的门限数字群签名方案.方案计算简单、实用,具有较好的安全性.     

多项式零点保持线性映射

设H是维数大于2的复Hilbert空间,β(H)代表H上所有有界线性算子全体．假定Φ是从β(H)到其自身的弱连续线性双射．我们证明了映射Φ满足对所有的A,B∈β(H),AB=BA~*蕴涵Φ(A)Φ(B)=Φ(B)Φ(A)~*当且仅当存在非零实数c和酉算子U∈(?)(H),使得Φ(A)=cUAU~*对所有的A∈β(H)成立．     

有限域上一类新的置换多项式

由于有限域上的置换多项式在密码、编码和组合设计有着重要的应用,置换多项式是人们比较感兴趣的一个研究课题.利用线性化多项式,得到了一类新的形如(x~(p~k)-x+δ)~s+L(x)的置换多项式.     

线性微分多项式的有穷值点及亏量总和

证明了线性微分多项式的一个基本定理,建立了线性微分多项式对有穷值的亏量关系,这些结果是对杨乐的两个定理的推广,例子表明,本文中定理的条件是必要的。     

关于有向网络容量扩充问题

提出了有向网络最大容量的两种计算方法,将杨超等人（1998）的无向网络容量扩充问题,扩展到约束条件含固定费用的有向网络的扩充,并给出了强多项式算法。     

对一群签名方案的分析与改进

通过对夏祥盛等人的动态门限群签名方案的研究,指出该方案的若干不足,其中最主要的不足是通过伪造和不可追踪性,并对该方案进行了改进．与现有群签名方案不同,新方案中用户的秘密数由用户自己选取,从而避免了双线性对的计算,大大提高了效率．分析说明改进的群签名方案几乎克服了原方案的所有缺点．     

有向拟阵和横截

讨论有向拟阵的横截理论，给出了Rado-Hall定理、Edmonds-Fulkerson定理的有向情形，从而部分地回答了[1]中的两个问题。     

有向面积及其应用

本文约定用〔ABC〕,〔AB… GH〕表示△ ABC,多边形 AB… GH的面积 .设 D、E、F是△ABC的 BC、CA、AB边上的点 ,且 BDDC=l,CEEA=m,AFF B=n,文〔1〕证明了〔DEF〕〔ABC〕=1 lmn( 1 l) ( 1 m) ( 1 n) . ( 1)文〔2〕进一步指出 ,若 D、E、F 是直线 BC、CA、AB上的点 ,且有向线段之比 BDDC=l,CEEA=m,AFF B=n,则〔DEF〕〔ABC〕=1 lmn( 1 l) ( 1 m) ( 1 n) . ( 2 )但文〔2〕未加证明 ,本文给出 ( 2 )的证明 .为此 ,先介绍多边形的有向面积 .设有△ A1 A2 A3 ,当其顶点绕行方向为逆时针方向时 ,记 S =〔A1 A2 A3 〕…     

基于身份的动态数字签名方案

数字签名是解决信息安全问题的重要途径,用于鉴别用户身份.随着计算机、网络的发展,安全的用户数字签名显得尤为重要.目前,现代的数字签名技术正向智能化、密码化、多因素、大容量和快速响应方向发展.结合数论中的中国剩余定理及RSA公钥体制,提出了一种基于身份的动态数字签名方案.     

基于线性码的新的秘密分享方案

A secret sharing system can be damaged when the dealer cheating occurs. In this paper,two kinds of secret sharing schemes based on linear code are proposed. One is a verifiable scheme which each participant can verify his own share from dealer‘s distribution and ensure each participant to receive valid share. Another does not have a trusted center, here, each participant plays a dual-role as the dealer and shadow(or share) provider in the whole scheme.     

Notes on linear factor polynomial deflation in polynomial bases

Scalar polynomials as approximations to more general scalar functions lead to the study of scalar polynomials represented in a variety of classical systems of polynomials, including orthogonal systems and Lagrange polynomials, for example. This article, motivated in part by analogy with the existing methods for linear factor polynomial deflation in the monomial basis, finds forward and backward deflation formulae for several such representations. It also finds the sensitivity factor of the deflation process for each representation.     

Security of meta-He digital signature scheme based on factoring and discrete logarithms

To enhance the security of signature schemes, Pon et al., recently, investigated all eight variants of the He’s digital signature scheme. The security of the proposed schemes is based on the difficulties of simultaneously solving the factoring and discrete logarithm problems with almost the same sizes of arithmetic modulus. This paper shows that the all eight variants of the He’s digital signature scheme, as well as two more variants, are not secure if attackers can solve discrete logarithm problems. Moreover, the attackers can easily forge signatures of the most optimal signature schemes of the generalized He’ signature schemes even though they can solve neither discrete logarithm problems nor factoring.     

Some fully polynomial time randomized approximation scheme based on an evolutionary algorithm

Considering the class of discrete optimization problems that satisfy the Woeginger conditions of existence of a fully polynomial-time approximation scheme, we propose a fully polynomial-time randomized approximation scheme based on an evolutionary algorithm.     

Power of statistical tests based on generalized separable statistics in the polynomial scheme

We investigate the asymptotic properties of statistical tests using generalized separable statistics in the polynomial scheme.Translated from Statisticheskie Metody Otsenivaniya i Proverki Gipotez, pp. 104–111, 1986.