Abstract: A first transfer device receives a first transaction signal from a second transfer device and provides a first certification signal. The second transfer device receives the first certification signal and encrypts it to provide a first encrypted signal. The first transfer device receives the first encrypted signal and encrypts the first certification signal to provide a second encrypted signal. A transaction is verified in accordance with the first and second encrypted signals and stored value is transferred between the first and second transfer devices in accordance with the verifying. A third transfer device, separate from the first and second transfer devices, receives a second transfer signal from a selected one of the first and second transfer devices and provides a second certification signal. The selected transfer device receives the second certification signal and encrypts it to provide a third encrypted signal.