A method and system are disclosed in an electronic payment network, for associating a payment card of a cardholder with a personal computing device of the cardholder, then authenticating the payment card in electronic transactions processed in the network. The card and a device activation code are input to the cardholder device by the cardholder, then communicated sent to a remote server for obtaining a card token. The server generates a device token and an authorisation token, stores the generated tokens together with the card token, and sends the card and device tokens to the cardholder device for storage. Whenever a transaction is processed in the network, the payment card is authenticated by inputting authenticating data to the cardholder device for generating an authorisation token, which is sent to the server with the stored card and device tokens, for a matching operation against the card, device and authorisation tokens at the server.