Each of multiple computing devices of a user is registered by obtaining therefrom identifying indicia, obtaining from the user a device-specific password for the computing device, and storing the obtained identifying indicia and device-specific password for the computing device in an entry for the user in a credentials database. The user requests access to a restricted service by way of a particular one of the multiple computing devices with credentials including the device-specific password for the particular computing device, and identifying indicia are obtained therefrom. The obtained identifying indicia and the device-specific password of the particular computing device appear in the entry, and the user is thus granted access to the restricted service.