在網路環境日益成熟的今日，網路交易的安全性已被列為首要的課題，而「公開金鑰基礎建設(public key infrastructure, PKI)」被公認是在資訊安全應用領域中，少數能同時滿足「保護資料安全」、「身分驗證」、「訊息完整性」以及「交易不可否認性」的加密應用技術。 電子商務被運用於各行各業，其中旅遊產業是全球最大與成長最快的產業之ㄧ。許多網路旅行社已經在企業內部建置了企業資源規劃(enterprise resource planning, ERP)系統，使得幾乎全部的交易與旅遊的安排都可以在線上完成。為了確保資料交換的安全性，便可以使用PKI技術，使企業的ERP 成為受完整加密保護的服務網路。 網路旅遊業者是以網站營運的方式來進行與消費者的互動，除了基本的防護措施，如：防火牆、入侵偵測、弱點掃瞄等網路安全外，企業的資安政策的制定與執行都可減少企業所面臨的風險。 近年來資料外洩事件頻傳，客戶資料及公司智慧財產外洩可能導致罰鍰、訴訟、公司品牌形象的毀損等。政府積極推動個人資料保護法，為了提高約束力，立法、司法與行政部門決定聯手祭出「天文數字的重罰」加以遏止；加上惡意使用者偽卡盜刷、冒名使用，使得電子商務業者不得不審慎地去評估如何加強資訊安全，以維繫企業本身的利益及提高企業的競爭力。 PKI的技術是目前公認最可靠、最可被信任的方式，但建置的複雜性及高成本，使得PKI的推廣層面不夠普及；如何讓PKI由「技術」移轉成為成功的「應用」，故筆者在本論文中建議一個運作模式，讓網路旅行社可以在透過網際網路行銷擴大業務之餘，也能因應時勢所趨，提供給其客戶一個安全的網路交易環境。 / The safety of Internet transaction has been referred to as the most important task in this fully-developed world of Internet. And public key infrastructure, which can provide confidentiality, authentication, integrity and non-repudiation, is one of the most effective ways of encryption in the application of information security. The travel agency has been one of the largest industries in e-commerce. There are many enterprise resource planning systems built in online travel agencies, so that almost every transaction and tours can be arranged through the Internet. To provide a well-protected environment, enterprises can use PKI technology to ensure the safety of online data exchanging. Online travel agencies interact with consumers through the web-site. Not only the basic protection like firewall, intrusion detection, and vulnerability scanning but also the development and the executive of security policies can reduce the risk that enterprises may encounter. Fines, litigations and the company's brand image damages may come after data leakages such as information of clients or intellectual property of companies. Government has actively promoted personal data protection law and huge amount of fines to improve the bindings. Coupled with many fraud credit cards used by the malicious users, companies have to assess how to reinforce information security to maintain its profit and upgrade its competitiveness. PKI technology is recognized as the most reliable and trusted solution, but the complexities and high cost of implementation made it difficult to apply. So, the author here tries to provide a mode of operation for online travel agencies to not only extend its services by the Internet but also provide a safe Internet transaction environment for its clients.