1. A method of registering a security token at a computing device, the method comprising: receiving, at a computing device, a security token identifier and a request to access one or more resources of the computing device, the security token identifier comprising static information that identifies a security token which has been presented at the computing device; sending, from the computing device to a server computing system, a request to identify domains having a trust relationship with a domain associated with the computing device; receiving, at the computing device from the server computing system, a response to the request to identify domains having a trust relationship with the domain associated with the computing device, the response comprising information that identifies one or more domains each having a trust relationship with the domain associated with the computing device; determining that an entry in a first data store matches the security token identifier, the first data store associated with a first domain of the one or more domains each having a trust relationship with the domain associated with the computing device; in response to the determining that an entry in the first data store matches the security token identifier, updating a local data store at the computing device such that, in the local data store, the security token identifier is associated with first domain information that identifies the first domain; and granting the requested access to one or more resources of the computing device based on the trust relationship determined to exist between the domain associated with the computing device and the first domain.