This disclosure describes techniques for performing enhanced authentication of a device based on physical proximity of the device to one or more other authenticated devices. An example method includes performing a first authentication of a first device or a first user and connecting the first device to a protected resource. Based on determining that the first device is within a threshold distance of a second, authenticated, device, a reauthentication interval is selected. Based on determining that the reauthentication interval has expired, a second authentication is initiated by transmitting, to the first device or a third device associated with the first user, a request for an authentication factor.