中文摘要：

针对基于XML的权限描述语言(如XrML和ODRL)的本质缺陷,提出了一种基于证书修改的数字权限动态描述模型。在定义了该模型的相关基本要素后,深入探讨和分析了该模型的执行过程,并给出了一个应用模型。

英文摘要：

Because of the intrinsical flaw of XML-based rights expression language such as XrML and ODRL,this paper demonstrated a kind of dynamic expression of digital rights by rewriting license.After defining the relevent essential elements of this model,it deeply explored and analyzed the execution flow.Finally,presented an application model.