The design and implementation of MPEG-21 players and authoring tools presents several critical points to be solved. One of the most relevant is the security level and protection processing in the players. This paper presents a solution for the realization of components in charge of enforcing Digital Rights Management in AXMEDIS tools for MPEG-21 digital content. The proposed architecture provides functionalities to create both trusted environment on the client side and dynamic protection and unprotection of digital content including digital resources and their organization and metadata. The same solution can be used to achieve the desired security level in any other MPEG-21 player or authoring tool. The architecture presented hereinafter has been adopted to enforce protection on authoring and player tools developed for the AXMEDIS IST FP6 R&D European Commission project.