Device, computer program and method

A device for authenticating a user, comprising:

• transceiver circuitry configured to receive motion information from a plurality of wearable devices located on a user's body indicative of the motion of the user's body at the location of the respective wearable device at a particular time, wherein the device is periodically updated with motion information to determine a continuous authentication score,
• in response to a request for authentication, transmit a synchronization signal to the plurality of wearable devices, and
• in response to transmitting the synchronization signal, receive, from each of the plurality of wearable devices, motion information and each wearable device's distance from each of other of the plurality wearable devices;
• and
• controller circuitry configured to
• compare the received motion information and the location of the respective wearable device, and
• authenticate the user in the event of a positive comparison between the received motion information and the location of the respective wearable device with stored motion information and the location of the respective wearable device,
• wherein the location of the respective wearable device is relative to each of wearable devices 1-N, where N is 3 or more, of the plurality of wearable devices, and the controller circuitry for successful authentication is further configured to
• receive, from each of the wearable devices 1-N, a distance between each of the wearable devices 1-N and the respective wearable device,
• determine that a sum of the distances between all of the plurality of wearable devices is within a predetermined threshold of a stored distance, and
• in response to a determination that the sum of the distances is within the predetermined threshold, achieve a higher level of authentication compared to N being less than 3 based on an inherent error in each distance measurement compounding and still being within the predetermined threshold.