【作者】 于宝证；

【导师】 徐枞巍；

【作者基本信息】 合肥工业大学 ， 电子商务， 2009， 博士

【摘要】 计算机和网络技术的发展将人类带入信息化社会并使得电子商务成为当前研究和应用的热门课题。而电子现金中使用的一些身份认证、密钥传输、数字签名和电子现金等信息安全技术是电子商务健康、持续发展的关键。本文在前人工作的基础上,比较系统地对电子现金及其使用的一些关键信息安全技术如:认证密钥交换、盲签名、群签名等的安全性进行了一些研究和探讨,在此基础上构建了一个多银行多面值的电子现金系统,并获得一些有意义的研究成果。对电子商务和电子现金的安全性以及电子现金关键技术的安全性的国内外研究现状进行研究,明确了本文研究的重点内容。对电子现金中使用的认证密钥交换协议进行了系统分析,研究了最近出现的两类典型的认证密钥交换协议的安全性和执行效率问题。对基于Diffen-Hellman问题的一类单/多认证密钥交换协议提出了一个通用的攻击策略,利用该攻击策略,可使得该类协议在某个共享密钥被泄露时,攻击者可以根据此信息,计算出用户以前或以后使用的共享密钥,从而不满足会话密钥的可知安全性。分析了预防该类攻击的防护策略并提出了一个改进的单/多认证密钥交换协议,新协议继承了以前方案的优点,但在共享密钥被泄露时,不会影响到后续共享密钥的安全性。跨服务器认证密钥交换一直是一个难题,对一类基于口令的跨服务器认证密钥交换协议的效率和安全性进行比较深入的研究。在改进原有协议的基础上,提出了一个更加安全和高效的基于口令的跨服务器认证密钥交换协议。对电子现金中使用的盲数字签名方案的构造和安全问题进行了系统分析。研究了最近出现的两个典型的盲签名协议的安全性。对两种盲签名方案分别提出了一种同态攻击、伪造攻击和小指数攻击新方法,分析了方案容易被攻击的原因所在,并在改进的基础上提出了一个新型的盲数字签名方案。对电子现金中使用的群数字签名方案的构造和安全问题进行了分析,研究了最近出现的两类典型的群签名协议的安全性。对一类基于离散对数的群签名方提出构造了签名伪造攻击和证书伪造攻击方法,证明该类签名是不安全的。对一类基于离散对数、大数因式分解和知识证明等几个难题假设的群签名方案构造了几类不同的签名伪造攻击和证书伪造攻击方法,并指出这些群签名方案不满足群签名所需要的不可连接性并分析了该类群签名存在安全隐患的原因,在改进的基础上设计了一个安全性更高的群签名方案。对电子现金的发展和构造问题进行了系统分析,研究了多银行离线电子现金安全性分析的拓扑结构并利用新提出的身份认证和数字签名技术,设计了一种多银行多面值电子现金方案。该电子现金方案克服了当前离线电子现金方案中银行进行多种面值现金发行时采用不同的公钥和私钥对进行区分的做法,银行只需保存一个私钥即可实现多种面值电子现金的发行。更多还原

【Abstract】 The development of computers and network technology has led human into informationized society and made e-commerce a top subject of research and application these days. To large extent, the crutial elements of e-commmerce’s healthy and sustainable development are the information security techniques such as identity authentication, key transmission, digital signature, and electronic cash. Based on the research of precedents, the paper has systematically explored fields including key exchange authentification, message recovery signature, blind signature, group signature, electronic signature and so forth, and has acheived significant fruits in the course of the research.Firstly, the paper comprehensively analyzes the authentication key agreement and discusses the security and efficiency of two typical categories of authentication key agreements. Furthermore,in order to deal with the Diffen-Hellman-based agreement, it puts forward a universal attack strategy, with which the attacker is able to caculate the user’s follow-up sharing key to unsatisfy the security of knowing the conversational key when a certain sharing key of such agreements is disclosed. To solve the problem, a protection strategy to prevent such attacks is analyzed and the author comes up with a modified and revised agreement of single/multi-key exchange. The new agreement inherits the merits of former plans and does not affect the security fo follow-up sharing key even if the share key is exposed. On the other hand, cross-server authentication key exchange remains a thorny obstacle. In addition, the security and efficency of password-based cross-server authentication key exchange agreement is also futher explored with the purpose to propose a secure and efficient agreement on the basis of the original agreement.Secondly, the paper analyzes the constrction and security of message recovery digital signature schemes y and does a lot of research on the security of two latest typical categories of message recovery digital signature agreements,which do not utilize Hash Functions. Two new forgery attacks on digital signature with message recovery are designs respetively and reasons for the forgery attack on schemes are figured out, which both attribute to two new secure schemes of digital signature with message recovery which do not use Hash Functions. While , compared with the old schemes,the efficency of both is equal, the security of the new schemes is improved quite a lot.Thirdly, the construction and security of blind digital signature schemes is analysed as a system and further expound the security of two newly-emerged typial blind signature agreements. The paper accordingly and seperately points out new approaches to handle with forgery attack, homomorphism attack and small exponent attack. Based on the analysis of reasons for being easily attacked, the author works out a new blind digital signature scheme.Fouthly, the author also analyzes the construction and security of group digital schemes and studies the security of two latest typical categories of group signature agreements. Aiming at discrete-logarithm-based group signature schemes, the author designs a new scheme of signature forgery attacke and certificate forgery attack to prove the such signature is insecure. Also, the paper points out several types of different signature and certificate forgery attacks to destroy the group signature with several hypothetic difficulties such as discrete logarithm, polynomials over a large infinite, knowledge proof and so on. Moreover, the author find out that these group signature schemes do not satisfy the needs of unconnectability which the group signature requires. In terms of reasons for the potential security risks, the paper puts up proposals for the future design of new secure group signature.Lastly, the paper systematically analyzes the development and construction of electronic cash and studies the staus quo of its development. Besides, the author,on the basis of the modification of Brands single-face value electronic cash scheme, proposes an effective one with diverse face value through the techniques of identity authentication and digital signature. The scheme makes use of discrete-logarithm-based constricted blind signature schemes to protect the user’s privacy and overcome the disadvantage of overloaded calculation with the technology of fair segmentation. The new scheme also enables banks to overcome the differentiation of public key and private key when banks issue cash with diverse face value according to recent off-line electronic cash schemes. With the help of a new method, the author innovates a simple scheme, where the bank is able to issue multi-face- value electronic cash with only one private key.更多还原