The eXpressive Internet Architecture (XIA) addresses the growing diversity of network use models, the need for trustworthy communication, and the growing set of stakeholders who coordinate their activities to provide Internet services. XIA addresses these needs by exploring the technical challenges in creating a single network that offers inherent support for communication between current communicating principals--including hosts, content, and services--while accommodating unknown future entities. For each type of principal, XIA defines a narrow waist that dictates the application programming interface (API) for communication and the network communication mechanisms. XIA provides intrinsic security in which the integrity and authenticity of communication is guaranteed. XIA enables flexible context-dependent mechanisms for establishing trust between the communicating principals, bridging the gap between human and intrinsically secure identifiers. This project includes user experiments..