Research On Security Mechanism Application In Electronic Bidding Based On Public Key Infrastructure

With the rapid development of information technology,the electronic bidding has been introduced and applied in the field of tender and bidding.However,the electronic bidding system,including some important information such as the tender,the designing proposal and the enterprise qualification,which contains the confidential information of the company such as the quotation,puts high requirement on the security of the system.The core of developing the electronic bidding system is to solve the security problems of the system which include identifying the authentication of users in the system strictly to ensure the confidentiality of the tender documents in the system,the integrity of the bidding documents in the transmission and the validity of the received tender documents as well as have an effective mechanism to prevent the sender of the tender documents from repudiating and prevent the tender documents from being tampered,etc.This thesis,concentrating on the application characteristics of the electronic bidding,has designed an electronic bidding security mechanism based on the Public Key Infrastructure(PKI)system by researching on the PKI security system,to solve the problems stated above.This security mechanism can verify the validity of the users,guarantee the integrity and safety of the electronic tender documents transported on the internet,verify the validity of the received files,and avoid the repudiation of the sender.As the tender documents are relatively too large,it would take a long time to encrypt the documents if we use the public key encryption directly,which will make the users have a frustrating experience.This thesis proposes a symmetric encryption key to encrypt the tender documents,which can enhance the efficiency of encrypting,while in the cost of reducing a small amount of safety performance,on the base of ensuring the security of the system.When it comes to deal with the security of the tender documents,this thesis introduces a combination solution concluding the virtual printing,the electronic signature and the time stamp.Firstly,the electronic document will be converted into the PDF format by virtual printing,which cannot be tampered,and then the document will be signed by the electronic signature and applied a time stamp from the Certificate Authority(CA).The electronic documents converted into PDF format have certain safety and reliability,and the electronic documents with the time stamps and the electronic seals will make the electronic documents be legal,which can be used as evidence to against the file sender from repudiation.This thesis proposes a way of using the USB Key with digital signature to solve the authentication problem.The digital certificate will verify the identities of both sides of the system,and the security mechanism of the USB key can secure the information,which can prevent forging the tender and leaking the data.At present,the electronic bidding system based on the security mechanism has been successfully developed and applied,which has been used safely and smoothly on the paperless bidding platform in a city of Hunan province for one year.