【作者】 王天银；

【导师】 张建中；

【作者基本信息】 陕西师范大学 ， 应用数学， 2005， 硕士

【摘要】 随着计算机通信网的迅速发展,人们希望通过电子设备实现快速、远距离的交易,数字签名应运而生,并开始应用于现实社会中。数字签名已经在信息安全、身份认证、数据完整性、不可否认性以及匿名性等方面发挥了重要作用。代理数字签名作为一种特殊的数字签名体制,可以实现普通数字签名无法解决的代理问题。代理数字签名的这种特殊性质使得它可以广泛应用于电子选举、移动通信、移动代理、电子商务等领域。自从1996年Mambo、Usuda和Okamoto首次提出代理数字签名概念以来,人们已提出了多种代理数字签名方案,如代理多重数字签名方案、门限代理数字签名方案以及盲代理数字签名方案等,代理数字签名的研究取得了丰硕的成果。然而,已提出的大多数代理数字签名方案在安全性、效率以及可行性等方面仍不够理想。因此设计安全、高效、可行的代理数字签名方案具有重要的现实意义。本文在这方面进行了一些有益的尝试和探索。 本文第一章为绪论,首先对代理数字签名的产生背景、现实意义和发展状况进行了介绍,第二章介绍了一些必要的相关数学和密码学知识,最后三章为本文核心部分,对已提出的几种典型的代理数字签名方案进行了分析,并提出了一些新的代理数字签名方案。 本文所取得的主要研究成果如下: 1 对两个门限代理数字签名方案进行了分析,证明了Q-C-X方案不能抵抗伪造攻击和公钥替换攻击,T-H-Y方案不能抵抗原始签名人的伪造攻击,并分别对这两个方案进行了改进,改进后的方案可以抵抗所提出的攻击。提出了一种新的具有已知签名者的不可否认门限代理数字签名方案,新方案具有计算量小、通信量低、安全性高等优点。 2 对两个代理盲数字签名方案进行了分析,证明了T-L-T方案和L-A方案不能抵抗伪造攻击和不具有不可链接性。提出了两种新的代理盲数字签名方案,新方案满足代理盲数字签名方案的安全性要求。 3 对一个前向安全的强代理数字签名方案进行了分析,证明了T-L方案不具有前向安全性。并分别基于Guillou-Quisquter签名体制和Schnorr签名体制,提出了两种新的前向安全的代理数字签名方案。更多还原

【Abstract】 With the rapid development of computer communication network, it is deeply hoped that people can finish their trading activities quickly in the distance by the means of electronic apparatus. As a result, digital signature came into being which is widely used in society. Digital signature has been playing a very important role in the fields of information security, identity authentication, data integrity, nonrepudiation and anonymity, etc. As a special digital signature scheme, proxy digital signature can settle some proxy problems which other normal digital signature schemes cann’t solve. Because of this particularity, proxy digital signature can be widely applied to many fields, such as e-election, mobile communication, mobile agent, e-commerce activities and so on. Since the year of 1996 when Mambo, Usuda and Okamoto firstly advanced the concept of proxy signature, many proxy signature schemes have been raised, such as proxy multi-signature scheme, threshold proxy signature scheme and proxy blind digital signature scheme. And plentiful achievements have been made in the studies of proxy digital signature. However, many proxy signature schemes have some defects in security, efficiency and feasibility. So it is of great significance to design secure, efficient and feasible proxy signature schemes. This paper made some meaningful attempts in the fields mentioned above.Chapterl, introduction of backgrounds in which proxy digital signature emerged, meaning in reality and development.Chapter2, introduction of some relative mathematics and cryptology.The following three chapters, the main part of this paper, in this part, the author analyzed several already-proposed classical proxy signature schemes and raised some new proxy signature schemes.The main contributions of this paper:1. Through the analysis of two threshold proxy signature schemes, we proved that Q-C-X scheme can’t resist forgery attack and public key substitute attack, and T-H-Y scheme can’t stand up to forgery attack from original signer. And some amendments have been made to both schemes. After the amendments, both schemes can resist attacks mentioned above. Moreover, a new nonrepudiable threshold proxy signature scheme with known signers was advanced which has features of less calculating amount, higher更多还原