During an NFC payment is the phone active or passive?

When somebody purchases something and 开发者_JAVA百科pays with google's NFC payment system (google wallet) , is the phone sending information to the register (if yes, what?) or is it just receiving the cashier's ID code, and then completing the transaction online (like dwolla)? -gk

during the payment the phone behaves exactly in a the same way as a contact-less payment plastic card (it is based on same ISO/IEC standards). Phone works in so called 'card-emulation' mode. The card is emulated in the secure element, which is highly protected chip. This chip can be so-far programmed only by Google or Samsung. Only those two manufacturers or possibly highly trusted 3rd party (currently I am not aware of any) companies have the possibility to use the build-in NXP SmartMX secure element. It means that nobody else can develop similar application like Google Wallet.

You can of course use other NFC HW for payment - the SIM card, but then you must deal with MNOs (Android SDK does not support the SWI officially), bluetooth NFC sticker or NFC SD card or SD card connected with NFC antenna via NFC-WI (S2C). Note that the last option is the best one, but is not supported by any phone.

You can also invent some proprietary payment system, which is less secure or which uses different schema like e.g. NFC PayPal application, which does not use the secure element, but the peer-to-peer mode for communication between phones. In this application the NFC is just the bearer to transport information - they can do the same over bluetooth or WiFi.

BR STeN