隨著網際網路以及資訊科技的日益進步,在網路這種虛擬的空間內,逐
漸產生一個資訊市集,每個人的日常生活未來將會與資訊市集相結合,舉凡
購物,理財,娛樂,從事工作,醫療,均可以在這個虛擬化的資訊市集裡找到
適當的服務.所以政府及企業也都相繼的把資料轉換成電子的形式,以利於
網路上傳遞與處理,以服務越來越多的網路族群. 但是在網路這種開放
式的環境裡,所傳遞的資料可能會遭到偽冒,攔截,監聽,竄改等等的惡意攻
擊,如果不想辦法解除網路上的威脅,那麼將會影響到資訊市集的形成,人
們也就感受不到網路技術所帶來的便利及好處. 為了解決上述網路通
訊上的問題,本論文利用憑證管理中心(CertificateAuthority)的幫助,實
作一套網路安全答錄機的系統,以解決兩兩間通訊的問題.另外本論文還利
用IC卡實體安全的特性來分配會議金鑰,並實作一套網路安全通訊系統,以
解決群體間通訊的問題,提供使用者加密,數位簽章以及資料完整性的服
務.

As Internet and information technology prevail, a new
marketplaceis gradually forming while the commercial
applications are becomingmore popular in the Cyberspace. This
new marketplace will have a great impact on people''s life while
appropriate services are being providedin many aspects like
shopping,financing,entertainment,medicine, etc.Observing the
trend, corporations as well as governments around theworld are
transforming their information into digital forms for
betterservices to the growing number of customers over the
Internet andhigher management capabilities. Since the Internet
is an open environment,messages being transferredover the net
are susceptible to interception,eavesdropping, espionage and
modification. This,the growth of the cybernetic marketplace is
limitedif these security threats cannot be effectively
controlled. People''slife will not benefit from the advanced
networking technologies. This thesis is a detailed
documentation of the implementation of a secure message
answering system with the help of a Certification Authority to
provide secure communication between any two entities. In
addition,a secure group communication system was also
implemented to provide secure communication services to a group
of users. The latter system takes advantage of the physical
security of IC-cards to distribute session keysand provide
security services such as encryption,digital signature anddata
integrity.