A method of authentication of a user is provided. The method comprises capturing a brain activity signal from a user； comparing the brain activity signal with reference data； and determining, based at least in part on the comparison, whether the identity of the user can be confirmed. Also provided is a computing device comprising at least one processor and at least one memory. The computing device is adapted to: communicate with a brain activity sensing system to capture a brain activity signal from the user； provide the captured brain activity signal to an authentication service computing system； and authenticate the user based at least in part on the result of a comparison with reference data received from the authentication service computing system. A system comprising the computing device and a brain activity sensing system, and am authentication service computing device are also provided.
