An opportunity for a computing device to participate in a secure session with a particular domain is identified. A secured microcontroller of the computing device is used to identify a secured, persistent seed corresponding to the particular domain and stored in secured memory of the computing device. A secure identifier is derived based on the seed and sent for use by the particular domain in authenticating the computing device to the particular domain for the secure session. The particular domain can further apply security policies to transactions involving the computing device and particular domain based at least in part on the secure identifier.