近年來，隨著雲端儲存技術的發展，愈來愈多的提供商提供了各式各樣的
雲端儲存服務。然而，每個提供商都提供了他們自己專屬的應用程式給使用
者，因此使用者必須安裝不同提供商所提供的專屬應用程式才能夠使用他們的
服務，這對同時使用多個雲端儲存服務的使用者造成非常大的不便。
而雲端儲存的安全性以及私密性則是另一個使用者會關心的重要議題。即
使大部分的提供商都宣稱這些儲存在雲端空間上的檔案皆安全無虞。但仍然有
使用者會擔心自己檔案的安全性以及私密性。
為了解決以上的情形，在論文中我們提出了一個可以整合多個雲端儲存空
間的架構，此架構可以同步使用者電腦以及多個雲端儲存空間中的檔案而不需
另外安裝他們個別的應用程式。另外，我們依然考慮了檔案安全性的問題，此
架構也另外提供了檔案加解密的服務，以增加儲存在雲端空間的檔案的安全
性。

In recent years, with the rapid development of cloud storage, many popular cloud storage service providers have been introduced. For example, the number of Dropbox users has risen to over one hundred and seventy-five million since 2007. By using this kind of service, users no longer need to take their data with them anytime. It is also increasingly easy to synchronize files across local devices and remote clouds. But because each of the providers provides their own application individually, it is an inconvenience for users to use their storage services at the same time across different providers.
The other issues of these services is privacy and security. Most of the cloud storages belong to "public" cloud storage. It means that the storages are managed by the providers instead of the users. Although these providers claim that they do not access users' data anyway, many users still worry about the privacy and potential security problems.
To solve these problems above, we proposed the architecture for integrating multiple cloud storages and synchronizing files between local computers and remote clouds automatically. We also implemented the file encryption and decryption functionalities for users to encrypt and decrypt their files before uploading to clouds.

Introduction 5
2 Related Work 8
2.1 MultCloud 8
2.2 Otixo 9
3 Algorithm 10
3.1 Rsync Algorithm 10
3.2 Rolling Checksum 11
3.3 Checksum Searching 12
4 System Architecture 14
4.1 Overview 14
4.2 Application 15
4.3 Server 16
5 Application Implementation 17
5.1 File detection 17
5.1.1 File Map Tree 18
5.1.2 File Created Event 19
5.1.3 File Deleted Event 20
5.1.4 File Renamed Event 21
5.1.5 File Motified Event 22
5.2 File Update Notication 23
6 Application Interface 24
6.1 Account Creation and Login Interface 24
6.2 Importing Multiple Accounts 25
6.3 File Encryption and Decryption Interface 26
7 Server Loading 27
7.1 Size of Checksum Table 27
7.2 Server Performance 28
8 Conclusion and Future Work 31
8.1 Conclusion 31
8.2 Future Work 32
Bibliography 33
A Server Implementation 35
A.1 Introduction 35
A.2 Hardware 36
A.3 Windows Communication Foundation (WCF) and Server Implementation 36
A.4 Large Data and Streaming 38
A.5 Database with Microsoft SQL Server 2012 38
B Encryption/Decryption Implementation 40
B.1 Introduction 40
B.2 Files Encryption and Decryption 41

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https://www.multcloud.com/.
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http://otixo.com/.
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http://jnotify.sourceforge.net/.
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https://www.dropbox.com/developers/core/docs.
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http://www.microsoft.com/zh-tw/download/details.aspx?id=29062.