The Design And Implementation Of An Electronic Seal System

Digital signature was promoted the seventies of last century,and it's very mature today,been used in almost everywhere.But in China,with traditional seals deeply taking root and without a creditable Public Key Infrastructure,almost all tax invoices,receipts,contracts,certificates and any other document which needs legal effects are still paper-based media,secured with traditional seals.They are risking high unsafety,and slowly in copy or transmission,incompatible to existing information systems,hindered the evolution of E-government and paperless office.Nowadays,with popularization of smartphone and mobile internet,meanwhile the Public Key Infrastructure building by government,conditions for popularizing electronic seal are mature,so it's time to promote the design and implementation of an electronic seal system.The technologies related with electronic seal are the same as digital signature,such as digital digest,asymmetric encryption,Public Key Infrastructure,Time Stamp Authorityn and so on,also need have in-depth knowledge about Portable Document Format.Considering the practice and compatible with traditional seals,analyzed requirements of electronic seal system and designed for it.Functionally the system can sign files,cancel signatures,verify signatures,extract signature information,login and provide timestamp server,then it's able to stamp single-page seal,multiple-page seals and cross-page seals to compatible with traditional seals,finally it should be flexible and adaptive.So there are server and client,server for information of signatures and on-line functions,core lib of client was written in python,adaptive with different document formats and encryption algorithms,providing APIs for CLI or GUI to separate logical layer and view layer,much flexible and adaptive.Finally,implemented the system meeting requirements and design,though the system also needs many improvements.Electronic seal system is based on digital signature,it combines the features of digital signature and traditional seal,but safer to use and easier to control,it's flexible and adoptive,and surely it's helpful for the popularization of digital signature in our country.