【作者】 黄岩渠；

【导师】 谢冬青；

【作者基本信息】 湖南大学 ， 计算机应用技术， 2004， 硕士

【摘要】 电子印章是应用层的数字签名，是电子签章的一种，由于文档签名与其他类型数据如程序，数据库数据等相比有其特殊性，本文针对文档签名的特殊性，如签名的可见与可证实性，文档的归档特性，文档阅读的方便性等进行了分析，指出文档实际上是一种格式化的数据，可以分为数据与格式两个部分，在此基础上提出了对文档进行签名的要求。 前向安全是数字签名应用提出的一个新要求，在要长期保存以备验证的文档中使用数字签名时显得更为重要，本文基于离散对数与求模n的平方根的难题提出了一种不需要额外存储空间的前向安全数字签名方案，该签名方案具有通常长度的公钥与私钥，在提出该签名的同时，给出了利用求模n的平方根的难题做密钥进化来构造前向安全数字签名方案的必要条件，并对该方案的安全性与性能进行了分析。本文把该前向安全数字签名方案应用在电子印章系统中，使得使用印章进行签章的文档具有前向安全性。 在对文档的签章中，把文档数据以及签名数据用XML数据来表示，把文档数据的签名转化为对通用数据对象的签名，由于XML签名规范是数据签名的标准，我们在对文档签章时对其签名元素进行了扩充，满足印章与前向安全签名的要求，同时利用文档转换来保证文档具有的相关特性。本文重点讨论了从RTF格式的文档到XML文档的转换，通过对转换程序的签名由可信的第三方来保证转换的安全性。 最后，本文利用基于文档前向安全签名的XML签名技术，建立了类似PKI的印章管理中心、印章注册机构的电子印章基础设施，给出了设计与验证的方案，印章信息与数字水印结合完成了在文档中电子签名与印章的统一，以印章图象来作为文档被签名的显示标志，并在数字水印中隐藏真实的文档签名信息；随后对建立的电子印章系统与公开密钥基础设施的相关组成部分进行了比较，在PKI基础上实现的电子印章系统，可以考虑与PKI整合，让电子印章系统成为PKI框架下的一部分。更多还原

【Abstract】 Electric seal is a method to sign a document and it is a kind of electric signature, though a document has some difference compare to other kind of data like program, data of a database, according the speciality of a electric signature to a document, such as view what we signed , validate the signature in a document directly, how to archives a document which has been signed, how to read a document has been archived, it points out that a document is exactly some data with some format data, a document could be disparted as two parts, data and format data. And put forward the requirement of a document signature.Forward-secure is a new requirement of digital signature, and it is even more important when signing a document for a document usually need to be put in pigeonhole. This paper uses some difficult mathematical problem like disperse logarithm and quadratic root hard problem to put forward a new forward-secure digital signature which need no superfluity storage. This signature scheme has a key’s length like other common signatures, and it gives some proposal on how to use quadratic root hard problem to let key evolve in a forward-secure scheme, this paper use the signature scheme in the seal system and get the forward-secure in a signature for a document.When we seal a document , we transit other document into XML data and changes the document signature to a common data object data signature, XML-signature syntax and processing is a standard to sign some data object, we revise and add some element to satisfy the requirement of seal and forward-secure digital signature, the security of transformation is protected by signing the transformation of the program, and the property of the document is also reserved.At last, this paper uses some forward-secure document signature’s XML signature scheme technic which we have introduce above, to establish a seal manage center , seal register organ which is PKI analog framework, and give a method of signature and validation. The message of seal embed into the digital watermark of seal picture , and use the seal picture as a symbol of signature of a document, the real signature data is also a part of the watermark in the picture; then compare the component of a electric seal system with the component of PKI, it considers implememt electric seal system on the fundamental of PKI, and let electric seal system become a part of PKI framework.更多还原