Abstract: Processing a touch input is disclosed. Information about a pending transaction is displayed. A touch input responsive to the displayed information is received. In the event the touch input indicates a first direction, the pending transaction is authorized. In the event the touch input indicates a second direction, the pending transaction is canceled.

Abstract: Communicating data is disclosed. A time delay encoding a data to be communicated is selected. A sonic signal is combined with a version of the sonic signal that is delayed by the selected time delay. The data is communicated at least in part by transmitting the combined signal to a mobile device.

Abstract: Indicating a request is disclosed. A transaction party identifier determined using an identification signal received via a first communication channel is received from a first communication party. A request is received from a second communication party identified by the transaction party identifier. It is identified that the first communication party provided the transaction party identifier associated with request. The request is indicated via a second communication channel to the first communication party.