由於網路的快速發展，網路購物交易變成人們生活不可或缺的一部分。雖然網路購物帶來方便性，但是它不像實體購物，透過面對面來執行交易認證，當下完成銀貨兩訖，並且有發票當作交易憑證，因此容易衍生問題。
在文獻上，有眾多提出安全性的機制及相關研究，例如:第三方交易平台機制、改良SET的安全機制，雖然有解決傳統無第三方交易平台的參與，仍無法有效解決交易認證的問題，例如:Online的交易認證模式容易產生第三方交易平台的效能瓶頸，除此之外存在單向作弊的風險，僅由單方與第三方做交易認證的動作，容易產生偽造及竄改的風險。
在本研究中，設計一個行動交易認證協定的機制，將傳統Online交易認證模式改良成Semi-Offline的P2P交易認證模式並且搭配NFC非接觸的特性，由買賣雙方P2P Online的方式做交易內容的交易認證，使得雙方當下可以得到交易認證檔並且解開比。另一方面雙方與第三方交易認證中心做Offline的交易糾紛處理，解決雙方的問題。Semi-Offline的P2P交易認證模式主要目的為解決單向交易作弊的風險，降低買方被欺騙的可能性，並且減輕第三方交易認證中心在傳統第三方交易平台所負擔的Overload。本研究機制除了達到網路購物交易的安全需求規範之外，也達到本研究所制定的雙向交易認證、雙向身分認證安全需求等功能。
根據執行效能分析比較之下，本系統的執行效能時間比傳統SET不管是否有數位信封的加密或其他市場上的機制更有效率，除此之外，在安全性方面也能跟SET相抗衡。因此本研究所提出來的協定不但適用於電子商務，更適合應用於行動裝置上。

In recent years, online shopping transaction has gradually evolved from e-commerce to m-commerce because handled mobile device grew rapidly. Furthermore, m-commerce provides a variety of services and applications and no limit of space and time for people.
Because of this, network security problem became the most important issue and most attention problem for online shopping transaction. The online shopping unlike traditional physical shopping, execute transaction authentication through by type of face to face, then finish transaction of the goods are delivered and the bill is cleared. Although many scholars proposed security mechanism to solve online shopping security problems and proposed related research to discuss them, those mechanism still cannot completely solve all online shopping security problems.
In this work, we improved traditional online transaction authentication mode to Semi-Offline P2P transaction authentication mode and match character of near field communication (NFC). The main purpose of the research is solved risk of one-way transaction cheating to achieve two-way transaction authentication and reduce TTAC overload. According to computing time of transaction authentication performance, demonstrating our proposed MTAP is more efficiency than traditional SET with digital envelope, traditional SET without digital envelope and other protocol in the current market. Therefore, we proposed protocol not only apply to e-commerce but also apply to m-commerce.

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