A method of authenticating a device and a user comprises obtaining a device ID for the device, performing a biometric measurement of the user, obtaining helper data for the user, and generating a key from the biometric measurement and helper data. There is then generated a message comprising the key or a component derived from the key, which transmitted to a remote service, and at the service there is carried out the step of authenticating the device and the user with the message. In a preferred embodiment, the generating of the key further comprises generating the key from the device ID.