具匿名性及安全性之B2C電子發票系統

電子發票是因應電子商務之發展，提供賣方營業人可以利用個人電腦，透過網際網路傳輸統一發票（簡稱電子發票）給買受人之作業。賣方營業人使用電子發票可以進行開立、作廢及列印電子發票，有節省郵寄發票成本、防止發票的遺失及縮短傳送發票時間等優點。買方營業人使用電子發票可以進行收取、退回、折讓及列印電子發票，有省下存放發票的倉儲空間及費用等優點。本研究以安全電子交易（Secure Electronic Transaction，簡稱為SET）協定為基礎設計可以匿名性及安全性之B2C電子發票系統（SET-B2CEIS，Secure Electronic Transaction–B2C E-Invoice System），以對稱式加解密、雜湊運算、三重簽章（Triple Signature）、數位信封、位元承諾（Bit Commitment）等技術作設計，提出一種SET-B2CEIS協定，使購買者的私密資訊不被洩漏，且交易過程可以有私密性、完整性、身份認證及不可否認性，避免第三者的破壞、塗改、洩漏或濫用，發生交易糾紛的情形。此外，本協定還可以有下列三項特性：（1）購買者同意捐贈電子發票後，電子發票的權利可以安全的由購買者轉移到受贈機關，購買者無法反悔捐贈且不再擁有兌獎的權利；（2）財政部可以稽核網購業者開立電子發票的正確性，避免網購業者逃漏稅的情形發生；（3）購買者可以匿名方式直接兌獎，網購業者不會主動兌獎，避免發生兌獎錯誤或未將中獎的發票紙本寄給購買者，且國稅局可以驗證得獎者的正確性，防止統一發票獎金被盜領。論文中我們以定性分析方式說明本電子發票系統何以在安全上及功能上滿足我們的設計目標，並且和採用SSL協定的現行紙本發票系統及現行電子發票系統作一比較。

關鍵字

電子發票； SET協定；對稱式加解密；雜湊運算；捐贈發票

並列摘要

E-Invoice is an operation through internet in which the seller can send invoice to buyer. It is an important element of the advancing E-Invoice. This research based on Secure Electronic Transaction (shorten as SET) protocol, is purposed to an anonymous and security B2C E-Invoice system (SET-B2CEIS, Secure Electronic Transaction-B2C E-Invoice System). This system is established on the technique of Symmetric Encryption, Hash function, Triple Signature, Digital Envelope, Bit Commitment. We develop a SET-B2CEIS protocol which can keep the privacy of buyer and the confidentially, integrity, authentication and, nonrepudiation of transaction in our protocol have three characteristics (1) Once the buyer decides to devote E-Invoice, the right of E-Invoice can be transferred safely to the receiver. The buyer can not regret devoting and do not have the right to convert the premium of uniform invoice. (2)The Ministry of Finance can check whether the merchant correctly send it the E-Invoice, which can avoid tax evasion; (3)Buyer can directly convert the premium of uniform invoice anonymously .The merchant can not convert the premium of uniform invoice actively to avoid converting incorrectly and avoid not sending the invoice paper to buyer. Besides, the Ministry of Finance can test and verify the correction of receiver, to prevent the premium miss-payed. In this paper we describe how this E-Invoice system can satisfy our goal in safety and function by qualitative analysis method, and we will compare our system with the practicing paper invoice system based on SSL protocol and practicing E-Invoice system.