應用於付費電視系統中限制存取系統的一個有效率且具彈性之金鑰分配架構

An Efficient and Flexible Key Distribution Scheme for Conditional Access System in Pay-TV Systems

謝丞宗(Cheng-Zong Shieh)

指導教授 ： 孫宏民

國立清華大學/電機資訊學院/資訊系統與應用研究所/碩士(2006年)

摘要

由於現代電腦網路科技及多媒體技術的蓬勃發展，近年來付費電視系統已成為最流行、熱門的應用之一。為了保護付費電視中的各頻道，限制存取系統(CAS)則是付費電視中最基本且必須的一項元件。透過限制存取系統的保護，只有被授權的訂閱者可以正確取得節目內容，同時，這些使用者需要根據訂閱的節目繳費。在本論文中，我們定義了一個名為彈性訂閱的付費電視模式讓使用者可以一次訂閱一群大量的頻道並且在付費期間中任意停止訂閱。為了達成此彈性訂閱機制的必要條件，我們提出了一個四層式金鑰管理架構的限制存取系統。本系統可以適用在大規模的付費電視環境中，允許大量使用者並容納大量的頻道。在本系統架構下使用者可以自由地選擇喜歡的頻道。除此之外，使用者亦可隨時任意的訂閱或取消某些頻道，並且，當發現非法使用者時，本系統亦可迅速撤銷其使用權限。

關鍵字

限制存取系統 ； 付費電視 ； 頻道保護 ； 階層式金鑰管理 ； 廣播加密法

並列摘要

The pay-TV system becomes one of the popular applications in recent years because of the advancement in modern network technique. The Conditional Access System (CAS) is the essential function to provide the channel protection in pay-TV system. Only the authorized subscribers can precisely receive the TV program, and they were charged by the service provider according to their subscription. In this paper, we defined a new pay-TV model named Flexible-PPC (F-PPC) which allowed subscribers subscribe to a large number of channels and unsubscribed each of them anytime. In order to accomplish the requirements of F-PPC, we also proposed a CAS with a four-level hierarchical key management scheme. The proposed CAS can be applied on a large scale pay-TV system with lots of subscribers and channels. The subscribers can freely choose the channels. Besides, subscribers can subscribe and unsubscribe channels arbitrarily, and the proposed CAS can also revoke illegal subscribers rapidly.

並列關鍵字

Conditional Access System (CAS) ； Pay-TV ； channel protection ； hierarchical key management ； broadcast encryption

參考文獻

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