Description I: A PHR-S needs to ensure that it is exchanging PHR information with the entities (applications, institutions, directories) it expects. This function depends on entity authorization and authentication to be available in the system. For example, a physician practice management application in a PHR-S might send claim attachment information to an external entity. To accomplish this, the application must use a secure routing method, which ensures that both the sender and receiving sides are authorized to engage in the information exchange. Known sources and destinations can be established in a static setup or they can be dynamically determined. Examples of a static setup are recordings of IP (Internet Protocol) addresses or recordings of DNS (Domain Name System) names. For dynamic determination of known sources and destinations, systems can use authentication mechanisms as described in TI.1. For example, the sending of a laboratory order from the PHR-S to a laboratory system within the same organization usually uses a simple static setup for routing. In contrast, sending a laboratory order to a reference laboratory outside of the organization will involve some kind of authentication process. Provision of a secure network infrastructure is beyond the scope of a PHR-S.