A method comprises a portable device obtaining a graphical encoded information item which is displayed on a display of a computing apparatus, decoding the encoded information from the encoded information item, and transmitting a first message to first server apparatus, the first message including the decoded information and a first identifier identifying the device or a user of the device, wherein the decoded information includes an apparatus identification information item for allowing identification of the computing apparatus, and the first server apparatus receiving the first message from the device, establishing the identity of the user of the device, wherein establishing the identity of the user comprises using the first identifier to determine if the user is registered with the first server apparatus in response to establishing the identity of the user, authorizing the user to access a service, and providing the service to the user via the computing apparatus using the apparatus identification information item or sending a second message to a second server apparatus, the second message including the apparatus identification information item and indicating that the user is authorized to access the service provided by the second server apparatus, the second server apparatus responding to receipt of the second message by providing the service to the user via the computing apparatus using the apparatus identification information item.