【作者】 张少平；

【导师】 胡宝霞；

【作者基本信息】 哈尔滨理工大学 ， 计算机软件与理论， 2005， 硕士

【摘要】 电子商务、电子政务使得网络上的商业活动和电子办公日益频繁,由此产生了大量的电子文档,而对于这些文档的生成、交易和签署等日期时间信息的存储、保护和证明也越来越重要,成为近几年来安全领域专家们热切关注的信息安全课题之一。数字时间戳是用来确定电子文档在何时创建和签署的一种技术,它也能用来比较两个有争议的电子文档的相关时间的先后,这对于那些对时间敏感的技术专利、机密文件、网上交易来说是非常重要的。此外,数字时间戳还可以为数字签名提供一个长久的有效期,有助于公钥基础设施(Public Key Infrastructure, PKI)的升级。而且,数字时间戳是PKI 的重要组成部分,是支持不可否认服务的关键因素。就当前现有的链接时间戳方案来说,仍存在着很多问题,它们不是查证效率低,就是数字时间戳的数据结构复杂、算法很难理解实现。本文则提出了一种新的基于轮的链接时间戳方案,其核心的概念是仍保持线性链接方案简单、提供相对时间证明的优点,但在轮的基础上对轮又进行轮的划分。当查证受质疑的时间戳时,只需抽取时间戳链上很小一部分的关键时间戳接点,来构成一条相对很短的时间戳查证路径。这样,一方面减小了查证计算的时间复杂度,提高了查证效率;另一方面,由于查证的效率大大提高,所以可选多个可信时间戳作为参照,进行重复查证,以保证查证的证据更具说服力。此外,文中对于时间戳系统的设计是以网络服务的形式来实现的。考虑到时间戳服务中对匿名性请求的需求,以及系统的可集成性,系统被设计为在面向网络服务体系结构下的订票服务、时间戳服务、时间源同步服务和公共路径服务及它们之间的交互。最后,为了能使各个服务间业务过程自动化的执行,文中给出了一个以网络服务的业务流程执行语言(Business Process Execution Language for Web Services, BPEL4WS)定义的流程描述。更多还原

【Abstract】 Web-based business activities and handling official business by computer is so frequently today in e-commerce and e-government, with producing a large number of electronic documents. To store, protect and verify the data of the date and time which takes place when electronic documents are produced, exchanged and signed becomes so important that security experts pay close attention to it in recent years. Digital time-stamping is a set of techniques enabling us to ascertain whether an electronic document was created or signed at a certain time. It can be used for verifying which of two disputable electronic documents is created earlier. It is very important to those which are sensitive to time include technical patents, secret intelligences and online trades. Besides, digital time-stamping improves security of PKI because of offering a long term of validity for digital signature. Digital time-stamping is important component of PKI and support un-repudiation. As to existing linking schemes for time-stamping, there are still some drawbacks unresolved. They are either costly in time-stamping verification or complication with understanding data structure and algorithm. The paper presents a new round-based linking time-stamping scheme. It creates large rounds with smaller rounds as well as takes advantage of linear linking scheme which is simple and supports relative temporal authentication. It needs a small fraction of the whole timestamp chain between two timestamps as key point to build a verifying chain when verification processes. In this way, it has reduced time complexity and computed with great efficiency in verification of timestamp chains; On the other hand, because the efficiency of verification improves greatly, a lot of trust timestamp available can be used for repeat verifications so as to ensure that the evidence verified has convincingness even more. In addition, the design of time-stamping system is realized in the form of web services in the article. The system is divided into four web services including ticket-booking, time-stamping, time source synchronization and public directory under the service-oriented architecture and operated through association among those web services. Meanwhile the system provides anonymous time-stamping service and can be easily integrated into other systems. At last, the paper presents a definition of process with BPEL4WS for business process from every web service being execution of automation.更多还原