由於網際網路上點對點檔案共享技術的蓬勃發展，使用者之間直接分享傳輸各種資訊日益增便，尤以多媒體數位內容為甚。然而，數位內容具有容易獲得、複製及散佈於網路上的特性。在其能增益網路創作機會之時，亦相對可能被濫用、非法複製、或剽竊等。這些非法行為將衝擊網路創作者分享其作品的意願。日前盛行的點對點分享軟體（例如：Napster, Gnutella, KaZaA, 與eDonkey等）就被廣用於分享有版權之音樂、電影及軟體等。因此網路創作之智慧財產權保護已是一個重要議題。我們需要一個有效且實用的系統來保護數位內容之版權以確保其經濟價值。

有鑑於此，本論文提出一個具版權保護之點對點網路數位內容分享系統，並融入數位版權管理概念。目的為使網路創作者能因分享其創作而獲益。此系統可保護其數位內容不被未付費授權而非法使用，並於傳輸過程中可阻擋多種網路攻擊。不僅保有在Conrado et al.中所提出的系統特性、修正其缺失、並提供更為強韌之安全考量，分別為：私密性、身份確認性、資料完整性、以及不可否認性等。我們希望藉由此系統的廣用以促進網路創作之發展。

Ever since the prevalence of Peer-to-Peer (P2P) file sharing technology over the Internet, it is more convenient for users to share and transmit information directly, especially in media digital contents. However, the characteristics of digital content are easy to be obtained, duplicated, and distributed through the network. When the use of digital content allows immense opportunities for creators, the ability for anyone to make perfect copies and the ease by which those copies can be distributed also facilitate misuse, illegal copying and distribution, plagiarism, and misappropriation. These illegal behaviors potentially impact creators to hesitate to publish their digital content creation. Popular Internet software based on a peer-to-peer (P2P) architecture (such as Napster, Gnutella, KaZaA, and eDonkey) has been used to share copyrighted music, movies, software, and other materials. Thus, the protection of IPR for network creators has become an emerging issue on Peer-to-Peer network. There is a great desire for an effective and practical system that can preserve the economic value of digital content and protect the rights of the owners.

In view of this, we present a right-protected digital content sharing system on Peer-to-Peer (P2P) network and utilizing Digital Rights Management (DRM) concept. The purpose is to allow creators can make profit from sharing digital content. Our proposed system can not only protect the rights of digital content from being used illegally, but also resist several attacks during transmitting process between peers and the server. It retains useful properties as those in Conrado et al.’s system, corrects its drawbacks and provides stronger security considerations including secrecy, Authentication, Integrity, and Non-repudiation. We expect the proposed system will become popular for more and more creators to share and spread their ideas.

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