文档介绍：南京航空航天大学
硕士学位论文
电子签章制作系统设计与开发
姓名:叶建国
申请学位级别:硕士
专业:航空宇航制造工程
指导教师:庄海军
20070101
南京航空航天大学硕士学位论文
摘要
目前,电子商务深刻地影响和改变了我们的生活,但随之而来的安全问题也
日益突出,电子签章系统便是保证电子商务安全的有效手段之一。电子签章系统
主要解决电子文件的签字盖章问题,用于辨识电子文件签署者的身份,保证文件
的完整性、真实性、可靠性和不可抵赖性。
本文对电子签章系统的签章图片制作技术、数字水印技术进行了深入的研
究,并开发了签章图片制作模块和数字水印模块。通过本系统,用户不但能制作
出常见的、具有传统审美价值的电子签章,更为重要的是还可以通过数字水印技
术对电子签章进行加密和防伪,保证了签章的合法性和安全性。本文主要的研究
工作如下:
(1)对常见签章及其特征进行了分类和归纳,设计实现了三种常见章型的印文
排列算法,并开发了签章制作模块。
(2)对彩色图像数字水印技术进行了研究,设计了一种基于混沌置乱和 DCT 变
换的数字水印嵌入和提取算法,实现了向任意尺寸的彩色图像中嵌入二值
水印的功能,克服了大多数数字水印算法对载体图像尺寸的限制。
(3)将数字水印技术应用于电子签章制作系统,实现了签章的加密和防伪功能,
有效地提高了签章图片的安全性。

关键词:电子签章,数字水印,DCT 变换,混沌置乱,图像处理

I
电子签章制作系统设计与开发
ABSTRACT
Nowadays, EC(merce) has developed quickly in our country,
and has influenced our lives widely. However, the security problem has arisen with
the development of EC. Fortunately, the scientists have found some efficient methods
to solve the problem. One of these methods is digital seal system, which appears
during the information construction. By the digital seal system we could sign our
names or stamp on the document. More importantly, we could know if the document
is integrated, actual and trustful, and make sure the document could not be denied.
Both the making method of digital seal picture and the digital watermarking
techniques are studied in the paper., and the author has developed a digital seal
making module and a digital watermarking module essfully. With the help of the
system, the user could make several kinds of seal pictures, and the digital
watermarking information can be hidden in the seal picture. Therefore the seal picture
is protected from being counterfeited. The main research work and achievements are
as follows:
(1) After studying on the actual seal, considering users’ requirement, the author
develop the seal making module, in which several arithmetic on how to arrange
the characters correctly in the seal are