When you provision a card to Apple Pay by taking a photo of your card or entering the info manually, what happens next is that the iPhone makes a call to the ca

When you provision a card to Apple Pay by taking a photo of your card or entering the info manually, what happens next is that the iPhone makes a call to the card network (Visa/MC/Amex) to verify the card data (the card network will also make a call to the issuing bank of the card for a validity check), and if all is well, the network will return the same information that is effectively provisioned to physical ICC chips that you see in newer credit/debit cards. These parameters are stored in the iPhone 6's secure element, and allow the iPhone to perform full EMV transactions. One difference between these parameters and those provisioned to a physical ICC on a new debit/credit card, is that the card number (PAN) is not used; instead a payment token is used (it looks like a PAN - it has the same number of digits, etc). This allows Apple Pay transactions to run on the same infrastructure as chip+pin/signature transactions.