A method of operating an add-on communicating with a mobile device for conducting financial transactions, the mobile device being configured to run a point of sale (POS) application, the mobile device comprising a central processing unit and a communication interface, the add-on comprising a contactless interface, a secure element and a controller to control wireless communications between the add-on and the mobile device, the method comprising:
- acquiring, via the contactless interface of the add-on, data associated with a payment apparatus, at least a portion of the data associated with the payment apparatus being solely accessible by the secure element;
- establishing, through a communication interface of at least one of a communication interface of the add-on or a communication interface of the mobile device, a secured communication channel between the secure element and a remote server;
- and
- sending over the secured communication channel, to the remote server, the at least a portion of the data associated with the payment apparatus so that a transaction authorization request may be processed.