隨選視訊系統交易授權之研製

Abstract

隨選即播視訊服務 (Video-On-Demand) 提供了使用者選擇影片及賞味時間的選擇權，並提供用戶端類似放影機般，播放、暫停、快轉或回轉等播放功能。用戶可以在工作閒暇之餘，挑選自己喜歡的影片來觀賞，是相當令眾人期待的服務。隨選視訊服務系統的資料一部影片的資料量通常有數百兆位元組 (gigabytes) ，龐大的資料量，對任何寬頻網路而言，也往往是頭號的頻寬殺手。如何提高系統的輸出效能，與有效利用網路頻寬是隨選視訊服務系統最熱門之討論主題。 在這篇論文中，我們結合了密碼方法之理論與隨選視訊服務系統，提出另一種的系統架構。在這個架構中，我們提供了安全的交談管道，保障客戶與服務提供者之間的交易對話，並提供足以充讓服務提供者（Service Provider）足以充分驗證的交易記錄，可以有效消弭服務提供者或客戶任何一方的不誠實所可能引起之交易糾紛。並在服務提供者保有Pay-per-view控制機制的前提下，可以將下載的影片資料重覆使用，不但提高資料的使用率，更可減低系統網路的資料總流量。

The VOD service provides provides an alternative means to view video information - user may select the movie they interested in schedule the user specified. VOD system has properties of massive data storage, massive data stream, and continuous playback. These properties are a tremendous challenge to the existing technologies. How to achieve highest system throughput, and how to make best efficiency of the bandwidth's usage, are the most popular topics in any discussions related to the VOD systems. In this paper, we proposed an alternative transaction system scheme which combined the cryptographic methods with VOD service to provided a nonrepudiation service to protect clients from incorrect service charges and provide service providers evidence to collect bills that are denied. It also provided the ability that clients can play unlimited times with downloading once only, under the proper access control. This can reduce lots of transmitting data flow to achieve more system throughput.