In this paper, we present our experiences concerning the enforcement of access rights extracted from ODRL-based digital contracts. We introduce the generalized Contract Schema (CoSa) which is an approach to provide a generic representation of contract information on top of rights expression languages. We give an overview of the design and implementation of the xoRELInterpreter software component. In particular, the xoRELInterpreter interprets digital contracts that are based on rights expression languages (e.g. ODRL or XrML) and builds a runtime CoSa object model. We describe how the xoRBAC access control component and the xoRELInterpreter component are used to enforce access rights that we extract from ODRL-based digital contracts. Thus, our approach describes how ODRL-based contracts can be used as a means to disseminate certain types of access control information in distributed systems. Categories and Subject Descriptors D.2.12 [Software Engineering]: Interoperability - Data mappin...