可替換式數位版權管理系統及其嵌入式裝置實作

Abstract

數位版權管理(digital right management, DRM)是一種概念，目的是控制數位媒體的消費和散佈，現在嵌入式媒體的裝置越來越普遍，也增加了數位版權管理的需求，因為在嵌入式媒體裝置上，實作數位版權管理系統是一種趨勢，各家公司各自發展了自己的數位版權管理系統，但這個現象產生了不同數位版權管理之間的溝通問題，除此之外，對消費者而言，不能夠在同一裝置上使用不同的數位版權管理系統，帶來了不方便。 在這篇論文中，我們提出了一種可替換式的數位版權管理系統，來達到在同一裝置上，使用不同數位版權管理的目的，在我們開始設計之前，我們必須先了解平台的特性，並且分析一些數位版權管理系統的架構，由此，我們找出最適合平台特性的一種數位版權管理系統，來做結合，然後我們根據這一種數位版權管理系統，提出一種可替換式的數位版權管理設計的概念，我們設計出一個數位版權管理模組的載入機制，這個載入機制能夠確認數位版權管理模組的合法性，並且把數位版權管理的工作放到數位版權管理的模組中，這個系統整合了下載工具的概念和OMA架構，有此來取得彈性和複雜性的平衡，最後，我們也在嵌入式系統平台上實作這個機制，用來證明這個機制的彈性功能。

Digital Rights Management (DRM) is a concept for controlling the distribution and consumption of digital media. As embedded multimedia devices are becoming popular, there are strong demands for the light-weight DRM systems that can run smoothly in a resource-limited environment. Because implementing the DRM in the embedded device becomes a trend, many companies create their private DRM on their device. However, this phenomenon causes the problem of interoperability between different DRM systems. In addition, from the consumer viewpoint, users can not use all kinds of DRM system on the same device. This is inconvenient for users. In this thesis, we propose a switchable DRM system to achieve the usage of different DRM systems on the same device. Before we design a switchable DRM system, we must understand the feature of the platform and analyze the structure of some DRM systems. After understanding them, we find an optimum integration of the platform and one DRM system. Then, we based on the designed DRM system to propose the concept of the DRM switchable design. We design an universal DRM module loader. This loader checks the validity of a loadable DRM module, and it defers all the other DRM tasks to the loaded module. This system integrates the concept of downloadable tools and the OMA architecture to provide a balance between flexibility and complexity. We also implement the mechanism on an embedded evaluation board to demonstrate its feasibility.