Design And Development Of A Digital Seal Making System

Nowadays, EC(Electronic Commerce) 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 successfully. 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 presented. An efficient method to code and decode image are suggested, too.(2) The digital watermarking techniques and the image processing techniques are researched deeply. Focus on how to embed colorized image with watermarking information clandestinely, the arithmetic based on chaos system and DCT transform is designed. According to the arithmetic, a digital watermarking system is developed successfully. The advantage of the system is that the size of carrier image and watermarking are discretional.(3) The digital seal making module and the digital watermarking module are integrated into a larger system, by which the users could encrypt the digital seal picture with digital watermarking.