植基於智慧卡上能有效阻止勒索的網路提款機電子現金轉帳系統

由於網際網路與行動通訊技術的蓬勃發展，使電子商務越來越普及。茲因犯罪行為日益遽增，所以如何防止惡意行為以及保護個人資產成為一項很重要之議題。在1983年，Chaum最早提出盲簽章的概念應用於電子現金系統上，之後有許多解決惡意行為的方案相繼被提出，但總是存在著某些爭議問題無法解決；直到2007年，Wang等人提出一個綜合改進方案，消弭多數爭議。不幸地，網路詐欺與勒索手法一再變更，一旦發生利用網路提款機進行勒索的案件，則Wang等人所提出的方案將面臨重大考驗，為了解決此一問題，我們提出一種植基於網路提款機上有效且具安全性的改進方案，使得犯罪者所指定的帳戶在勒索的情況下會被追蹤，儘管轉帳的程序依然進行著，等到轉帳程序完成後，這個問題帳戶就會被凍結，使歹徒無法得逞。無論對於被害者或是犯罪者，我們提出的方案都可以避免惡意的行為。

關鍵字

電子現金；勒索；網路ATM ；不可否認性；交互認證

並列摘要

With the development of Internet and mobile technologies, E-Commerce has been popular. Because the crime is thriving, how to against malicious behavior and protect the victim's property becomes an important issue. In 1983, Chaum was the first person to propose the concept of blind signature applied in E-cash System. Moreover, there are more and more applications to solve malicious manner were presented. But there are always some disputes. Wang et al. proposed the improved scheme to solve these problems until 2007. Unfortunately, the trick of deception and blackmail are changeable again and again. Once the blackmail occurs on the Net-ATM, the Wang et al.'s scheme will be confronted the challenge. To solve this problem, we proposed a smart card based E-cash transfer system against blackmail on the Net-ATM scheme. The problematic account which is designated by the criminal is able to be traced under the blackmail. And the transfer is still running without altering the criminal. After the transfer is finished, the problematic account will be frozen. However, the criminal doesn't know the designated account has been frozen. Therefore, when he/she goes to withdraw the money, he/she will not achieve his/her purpose. For victims or criminals, the proposed protocol can also prevent a malicious behavior.