XeNA is a new model for the negotiation of access within an extended eXtensible Access Control Markup Language (XACML) architecture. We bring together trust management through a negotiation process and access control management within the same architecture. The negotiation process based on resource classification methodology occurs before the access control management. A negotiation module at the core of this negotiation process is in charge of collecting resources required to establish a level of trust and to insure a successful evaluation of access. The access control management is based on an extended Role-Based Access Control (RBAC) profile of XACML. This extended profile responds to advanced access control requirements and allows the expression of several access control models within XACML.