共查询到17条相似文献,搜索用时 93 毫秒
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随着公钥基础设施PKI技术的发展与应用,重要文档、商业合同和电子交易等信息都需要一种准确、权威的时间戳服务,本文主要分析了时间戳服务系统设计的方法和关键技术,提出了一种时间戳服务系统的设计方案,指出了对时间戳管理的基本要求。 相似文献
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数字签名方案采用公钥加密技术确保了文档数据的完整性、真实性和不可抵赖性,但是它是时间不敏感性的.可能使得签名含有相同的时间而发生冲突。本文引入了可信时间戳概念来解决这个问题,设计了一种带有时间戳的XML数字签名方案。 相似文献
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由于网络环境及各种外部条件导致有些网络的数据传输受到影响,网络时断时续,传输速度时快时慢,在这种情况下,的时间戳应用较为困难。就此情况提出了一种时间戳应用方案,通过引入了可信计算平台技术,利用可信计算平台模块中的滴答计数器与时间戳服务器相结合的方法,实现了在此种不可靠网络环境中的时间戳服务。 相似文献
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带有时间戳的数字签名方案的安全性分析 总被引:1,自引:0,他引:1
本文从时间戳的概念出发,分析了时间戳的权威性和可信性;给出了带有时间戳的数字签名方案,从数字文件加上时间戳的实现过程中,逐步分析了带有时间戳的数字签名方案的安全性问题和解决方法,并进一步分析了影响时间戳进度的因素。 相似文献
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数字时间戳(DTS)技术被广泛用于数字签名、电子商务及各种软硬件产品的专利和产权保护。在一些网络状况差、网速变化大、时断时续的不可靠网络中,缺乏必要的技术手段来保证时间戳服务的正常、有效运行。根据不可靠网络的特点,设计了一个不实时依赖时间戳服务中心(TSA)的时间服务模型,每次进行时间戳服务时不再需要与远程TSA进行通信,而是通过本地可信平台来进行时间戳服务。还提出一种不可靠网络环境下基于可信平台模块(TPM)的数字时间戳服务协议,并对协议进行了安全性分析。结果表明,协议是安全的,协议产生的时间误差是可控的,对不可靠网络有很好的适应性。 相似文献
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《Journal of Computer and System Sciences》2006,72(4):690-705
To ensure integrity and originality of digital information, digital signatures were proposed to provide both authority and non-repudiation. However, without an authenticated time-stamp, we can neither trust signed documents when the signers' signature key was lost, stolen, or accidentally compromised, nor solve the cases when the signer himself repudiates the signing, claiming that has accidentally lost his signature key. To withstand forward forgery suffered by linking schemes and to reduce verification cost, Sun et al. proposed four time-stamped signature schemes that are based on absolute temporal authentication. Though Sun et al. claimed that these schemes are quite secure against the forward forgery, we find that they suffered from substitution attacks, by which the signer can backward/forward forge signatures and the time-stamping service can also forge signatures. Finally, we also propose four time-stamped signature schemes to overcome these security flaws. Moreover, the proposed new schemes are more efficient than the Sun et al. schemes. 相似文献
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Mummoorthy Murugesan Wei Jiang Chris Clifton Luo Si Jaideep Vaidya 《The VLDB Journal The International Journal on Very Large Data Bases》2010,19(4):457-475
Similar document detection plays important roles in many applications, such as file management, copyright protection, plagiarism
prevention, and duplicate submission detection. The state of the art protocols assume that the contents of files stored on
a server (or multiple servers) are directly accessible. However, this makes such protocols unsuitable for any environment
where the documents themselves are sensitive and cannot be openly read. Essentially, this assumption limits more practical
applications, e.g., detecting plagiarized documents between two conferences, where submissions are confidential. We propose
novel protocols to detect similar documents between two entities where documents cannot be openly shared with each other.
The similarity measure used can be a simple cosine similarity on entire documents or on document fragments, enabling detection of partial
copying. We conduct extensive experiments to show the practical value of the proposed protocols. While the proposed base protocols
are much more efficient than the general secure multiparty computation based solutions, they are still slow for large document
sets. We then investigate a clustering based approach that significantly reduces the running time and achieves over 90% of
accuracy in our experiments. This makes secure similar document detection both practical and feasible. 相似文献
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IEEE1588协议硬件时间戳标记电路设计 总被引:1,自引:0,他引:1
IEEE1588协议是一种基于网络多播技术的精密时钟同步协议,为了提高时钟同步的精度,提出了一种在以太网物理层和MAC层之间的介质无关接口(MII/RMII)处检测同步报文的策略和实现精确时间戳标记方案,在此方案基础上设计和实现了基于FP-GA的硬件时间戳标记电路;设计了相关测试平台,对设计电路进行了测试和验证,测试结果表明设计的时间戳标记电路可以在RMII接口处实时地标记同步报文的收发时间戳,设计达到课题要求,应用性能良好。 相似文献
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基于通用PC架构的高精度网络时延测量方法 总被引:16,自引:0,他引:16
时延是准确测量时延抖动、带宽等网络性能指标的基础.目前的时延测量方法由于存在时钟误差和位置误差因而精度较差.提出一种改进的时延测量方法,以TSC(time stamp counter)寄存器取代系统时钟计时来消除测量的时钟误差,将时间戳记录位置由应用程序转移到网卡驱动来消除位置误差,极大地提高了时延测量精度.实验结果表明,与传统方法相比,不同包长度下,所提出的方法可降低测量误差21%~150%,且测量结果稳定,对系统吞吐量基本无影响.该方法基于通用PC架构,测量成本低,适于普遍采用. 相似文献
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Work-centered digital information services are a set of library-like services meant to address work group needs. Workplace users especially need to access legacy documents and external collections. They also frequently want to retrieve information (rather than documents per se), and they require that digital information systems be integrated into established work practices. Realizing work-centered digital information systems requires a broad technical agenda. Three types of analysis-document image, natural language, and computer vision, are necessary to facilitate information extraction. Users also need new user interface paradigms and authoring tools to better access multimedia information, as well as improved protocols for client-program interaction with repositories (collections). Moreover, entirely new types of documents must be developed to exploit these capabilities. The system developed by the authors follows a client-server architecture, in which the servers are repositories implemented as databases supporting user-defined functions and user-defined access methods. The repositories also serve as indexing servers. The authors are creating a prototype set of information services called the California Environmental Digital Information System, which includes a diverse collection of environmental data 相似文献
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对象行为协议对于辅助其他开发者理解并正确使用对象所提供的外部行为具有十分重要的意义.然而相关文档却常常缺失或存在不一致,需要通过逆向分析的方法进行恢复.针对这一问题,本文提出了一种基于驱动执行和动态分析的对象状态机(Object State Machine,OSM)提取方法.该方法从源代码中提取包含类属性的条件表达式,以其在运行时刻的取值情况及程序异常信息作为状态标识,并通过驱动执行的方式获取运行时的状态转换信息,然后分析运行时信息逐步构造对象状态机.该方法已实现为相应的原型系统,初步实验结果表明通过该方法可以高效、准确地恢复对象行为协议. 相似文献