An Extensible Semantics for XrML

Опубликовано 7 сентября 2016, 16:05

The eXtensible Rights Markup Language (XrML) is becoming an increasingly popular language in which to write software licenses. When first released in 2000, XrML received the support of many companies, including Adobe Systems, Hewlett-Packard Laboratories, Microsoft, Xerox, and Barnesandnoble.com. More recently, XrML has formed the basis for an ISO standard that was released in March 2004. Unfortunately, the standard does not provide an efficient algorithm for determining whether a permission follows from a set of XrML licenses and, despite its name, the languageΓÇÖs extensibility is limited. After presenting an overview of the standard, I address these issues by first giving a translation from XrML licenses to formulas in first-order modal logic. Then I apply techniques from the formal methods community to find an appropriate algorithm and investigate extensions.