臺灣博碩士論文加值系統

雲端儲存近年來相當普及，從企業到個人皆可能使用雲端儲存服務，將大量的資料存入雲端服務提供者 (Cloud Service Provider)提供的雲端空間中。然而『資訊安全』議題如資料的機密性與完整性是使用者是否願意將資料儲存於雲端的重要考量。本篇論文利用『自動化雲端稽核系統』，使用公正的第三方(trusted third-party auditor)進行加密資料的驗證，如此一來可保障使用者資料的機密性、完整性，以及雲端系統的可用性。考量到多人驗證的效率問題，本篇論文亦設計批次驗證功能來一次驗證多使用者的多個檔案。同時，系統設計也提供錯誤檔案搜尋功能，協助使用者發覺雲端儲存上未經授權的檔案修改，達到更完善的檔案稽核。

Cloud storage service is one of the most popular applications due to its convenience, easy manipulation, and some free cloud storage volume. However, security issues such as data pri- vacy,data integrity and the system availability has been vital challenges on cloud storage service. In this paper, we propose a scheme with a trusted third-party auditor (TPA) doing both single user auditing and batch auditing for multiple users. Both auditing algorithms are designed un- der the structure with all files encrypted. Thus TPA cannot catch any confidential information during the process of verification. Moreover, our system can extract corrupted files if the veri- fication fails, which help user realize which file has been modified.

摘要 ..................................i
Abstract ..................................i
致謝 ..................................iii
Contents ..................................iv
List of Figure ..................................v
List of Table ..................................vii
1 INTRODUCTION ..................................1
2 RELATED WORK ..................................4
3 PROBLEM STATEMENT ..................................7
3.1 ThreatModel ................................... 7 3.2 SystemGoal.................................... 8
4 SYSTEM ARCHITECTURE ..................................9
4.1 Preliminaries ................................... 9
4.1.1 SystemInitialization ........................... 9
4.1.2 Merkle HashTree............................. 10
4.1.3 Two-layer Merkle HashTree....................... 11
4.2 SingleUserAuditing ............................... 11
4.3 BatchAuditing .................................. 13
4.4 CorruptedFileExtraction............................. 14
5 IMPLEMENTATION ..................................16
5.1 UserInterface................................... 16
5.2 SingleUserAuditing ............................... 17
5.3 BatchAuditing .................................. 19
5.4 CorruptedFileExtraction............................. 19
5.5 AvailabilityDetection............................... 21
6 EVALUATION ..................................22
6.1 SecurityDiscussion................................ 22
6.2 PerformanceEfficiency.............................. 23
6.2.1 TheInfluenceofDifferentUserNumber. . . . . . . . . . . . . . . . . 23 6.2.2 TheInfluenceofDifferentFileNumber ................. 24
7 CONCLUSION ..................................26
Reference ..................................27
Appendix ..................................30

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