> After you authenticate your transaction, the Secure Element provides your Device Account Number and a transaction-specific dynamic security code to the store’s point of sale terminal along with additional information needed to complete the transaction. Again, neither Apple nor your device sends your actual payment card number. Before they approve the payment, your bank, card issuer, or payment network can verify your payment information by checking the dynamic security code to make sure that it’s unique and tied to your device.
> Like with in-store payments, Apple sends your Device Account Number to the app or website along with the transaction-specific dynamic security code. Neither Apple nor your device sends your actual payment card number to the app.
Note that this can be prefaced by 'usually' - some banks, instead of generating a new unique ID for Apple Pay, will use the CC number itself, or will at least augment the device ID with the payment card (I noticed this as receipts showed the last 4 of the card, despite using Apple Pay).
