臺灣博碩士論文加值系統

網路日愈普及下，我們的生活型態正逐漸朝向無現金社會發展，現金
、紙鈔及支票即將電子化，未來人們將不再持有實實在在的現金、鈔票和
支票，所有的錢都將只是一些電子數據，因此電子現金(electronic
cash)、電子支票(electronic check)將因應而生。不幸的是，電子現金
和電子支票也將面臨金融犯罪的威脅，比如偽造、盜拷、重覆使用等問題
。本論文提出安全電子支付系統之研究，之中研究電子現金、電子支票及
電子轉帳(electronic fund transfer)之安全處理程序。(1)在電子現金
方面:本文研究事先防止超額花費的電子現金系統，主要依據智慧卡(
smart card)及客戶電腦組成的電子皮包(electronic wallet)概念，在智
慧卡中設計有提款計數器和消費計數器，每次消費之前，智慧卡皆核算確
定累計消費金額小於提款金額時，才允許客戶消費，而且配合智慧卡內部
數位簽章(digital signature)的運作，共同解決電子現金所面臨超額花
費的問題。(2)在電子支票方面:本文提出沿襲紙張支票的使用行為，後手
擁有驗證前手簽章的方式，由於區別計算量的不同，在此分為各個前手簽
章逐一驗證的方式及前手組合而成的合成簽章的驗證方式兩種。後手傳送
收到的電子支票給銀行，銀行則針對記錄在客戶指標流向的經手者身分逐
一的取出其公開金匙來作驗證，這樣的系統建立一個可追蹤、不能盜拷、
不能偽造及不能重覆使用的電子支票系統。再者，提出本行電子支票(
cashier's check)系統。(3)最後在電子轉帳方面：本文提出網路轉帳的
方法，將來合法個人皆能利用網際網路且不受時間空間的限制達到資金轉
移的目的，當中使用數位簽章配合詢問/應答(challenge /response)方法
，使得重覆攻擊(replay)的威脅不會成功，且第三者也不可能偽冒成功，
達到保障客戶在銀行間的轉帳交易安全。

Under the extraordinary growth of international
interconnected computer networks, the paperless society is
coming true soon. Both cash and checks will be processed in
electronic form. Money will be only a lot of electronic data
that have been manipulated by the bank. Unfortunately,
electronic cash and electronic check systems are under the
threats derived from financial crime. In this thesis, some
effective methods are proposed for secure electronic payment
systems that include (1) electronic cash system without
overspending, (2) secure electronic check system, and (3)
network fund transfer. In electronic cash, we present how a
smart card can be incorporated in the protocols to provide prior
restraint against overspending by the customer, instead of just
detection after the fact. A withdrawal counter and a payment
counter are inside the smart card. Before payment, the smart
card first checks whether the accumulated amounts of the payment
counter are less than the withdrawal amounts. If yes, then the
customer can pay electronic cash for this consume. In addition,
we arrange the digital signature scheme in smart card. By this
two concepts, we accomplish the goal that the customer can not
spend more electronic cash than withdrawn by the customer. To
secure electronic check, we use the method that system
operations of which based on paper check. A current payee can
verify the previous digital signatures. Owing to different
computable complexity, we present how every previous signature
and composite previous signatures can be verified. The payee
also sends received electronic check to the bank for verifying.
By this method, we can establish a traceable, unforged and
unduplicated electronic check system. Furthermore, the secure
electronic cashier*s check is also discussed. Finally, the
method of network fund transfer is proposed. In this method, we
adopt digital signature and challenge/response protocols to
prevent replay attack and cheating. It makes people who are
legal and authorized can take advantage of world wide web to
conduct funds transfer safely.