隨著雲端服務的增長，像是Amazon, Yahoo!, Google Drive, Dropbox and iCloud，這些雲端服務提供商，提供了使用者可擴展性的資料儲存服務，且比起傳統的方法更有效率。像是我們會使用這些來儲存我們的電子郵件、線上備份、圖片或是一些重要的文件，但由於儲存在雲端上的資料可能因為一些軟硬上的錯誤或是人為因素，輕易的就遺失或是毀壞，因此驗證在雲端上的資料完整性就成為了關鍵的議題。為了解決這個問題，近年來，有許多的方法都已經被提出來了，但不幸的是，這些方法都只針對個人資料做探討。
在此篇論文中，我們認為群組的資料是非常重要的，像是遺囑、企業間的合約和國與國之間的合約，因此我們針對群組的資料提出了一個驗證協定，並採用學者張等人所提出的短簽章協定及學者蔡所提出的具認證性群組秘鑰協商協定，來增強我們的安全性。

An increasing number of cloud services, such as Amazon, Yahoo!, Google Drive, Dropbox, and iCloud, provides efficient and scalable data storage services at a considerably lower marginal cost than providers employing traditional ap-proaches. Uses of this type of storage include online data backup, photo sharing, and applications related to email and crucial documents. However, data stored in a cloud are vulnerable to loss, corruption through hardware and software fail-ures, and human errors. Thus, verifying the authenticity of data has emerged as a critical concern regarding data storage on cloud servers.
To address the vulnerabilities of cloud-stored data, many approaches have been proposed. However, most of these approaches focus only on the data of indi-vidual users.
This study addressed the data of groups and focused on categories that are generally considered crucial: testaments, vital contracts between organizations, and contracts between countries. Thus, to improve the security of cloud-stored group data, a verification protocol for group users based on the short signature protocol developed by Zhang et al. and the authenticated group key agreement protocol developed by Tsai is proposed.

中文摘要I
Abstract II
誌謝 III
CONTENTS IV
List of FiguresV
List of TablesVI
Chapter 1 Introduction1
Chapter 2 Related work4
Chapter 3 The proposed protocol12
3.1 Description and Assumption12
3.2 Notations14
3.3 Storing procedure15
3.4 Querying procedure16
3.5 Data integrity verification17
Chapter 4 Security Analysis 20
Chapter 5 Conclusions26
References 27

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