A method of performing an electronic transaction using a system comprising a mobile device, a plurality of authentication systems and a plurality of service facilitator systems, the method comprising: communicating, via a transaction element, transaction data relating to the electronic transaction to the mobile device; confirming, by the user, of the transaction data and transmitting from the mobile device a confirmation message to the transaction element; receiving (302, 402), by a first service facilitator system of said plurality of service facilitator systems, transaction data relating to the transaction in an electronic transaction request from the transaction element; generating, by the first service facilitator system, a transaction identifier associated with the transaction; transmitting (303, 303', 404) the transaction identifier to the mobile device, wherein the transaction identifier is part of an electronic token that includes an identifier of the first service facilitator system; wirelessly transmitting (304, 406), by the mobile device, a transaction initialisation request to a first authentication system among said plurality of authentication systems, which is the one known to the mobile device, the transaction initialisation request comprising the transaction identifier; identifying, by the first authentication system, the first service facilitator system among said plurality of service facilitator systems on the basis of said identifier of the first service facilitator system; transmitting (305, 408), by the first authentication system, the transaction identifier to the first service facilitator system; providing, by the first service facilitator system in response to the reception by the first service facilitator system of the transaction identifier, at least some of the transaction data to the first authentication system; authenticating the mobile device by the first authentication system (306, 410); generating, by the first authentication system, a transaction execution command; transmitting, by the first authentication system, the transaction execution command to the first service facilitator system; and executing (308, 412), by the first service facilitator system, at least part of the electronic transaction. communicating, via a transaction element, transaction data relating to the electronic transaction to the mobile device; confirming, by the user, of the transaction data and transmitting from the mobile device a confirmation message to the transaction element; receiving (302, 402), by a first service facilitator system of said plurality of service facilitator systems, transaction data relating to the transaction in an electronic transaction request from the transaction element; generating, by the first service facilitator system, a transaction identifier associated with the transaction; transmitting (303, 303', 404) the transaction identifier to the mobile device, wherein the transaction identifier is part of an electronic token that includes an identifier of the first service facilitator system; wirelessly transmitting (304, 406), by the mobile device, a transaction initialisation request to a first authentication system among said plurality of authentication systems, which is the one known to the mobile device, the transaction initialisation request comprising the transaction identifier; identifying, by the first authentication system, the first service facilitator system among said plurality of service facilitator systems on the basis of said identifier of the first service facilitator system; transmitting (305, 408), by the first authentication system, the transaction identifier to the first service facilitator system; providing, by the first service facilitator system in response to the reception by the first service facilitator system of the transaction identifier, at least some of the transaction data to the first authentication system; authenticating the mobile device by the first authentication system (306, 410); generating, by the first authentication system, a transaction execution command; transmitting, by the first authentication system, the transaction execution command to the first service facilitator system; and executing (308, 412), by the first service facilitator system, at least part of the electronic transaction.