How Tap to Cash Uses NFC in iOS 18

Apple’s iOS 18 introduces Tap to Cash, a feature that allows users to send and receive Apple Cash simply by holding two iPhones together. This article explains how the feature combines short-range Near Field Communication (NFC) technology, hardware-level security, and biometric authentication to facilitate instant peer-to-peer payments without requiring users to exchange phone numbers, email addresses, or other personal contact information.

Initiating the Transaction

Tap to Cash begins in the Apple Wallet app or Control Center. The sender specifies the amount to transfer and authenticates the intent using Face ID, Touch ID, or a passcode. This initial authentication step ensures that funds cannot be transferred accidentally or without the account holder's explicit consent. Once authorized, the device enters a state ready to establish a secure, local peer-to-peer session.

NFC Proximity and Session Establishment

When the top edges of two iPhones are brought within centimeters of each other, their built-in NFC chips detect the proximity, mirroring the mechanism used by Apple's NameDrop. Because NFC operates only over extremely short distances—typically under four centimeters—the physical proximity requirement prevents unauthorized remote interception or accidental transactions from nearby devices. The NFC chips exchange an encrypted handshake that establishes a temporary, private connection specifically designated for the pending transaction.

Hardware-Level Encryption and the Secure Element

The actual financial data is managed by the iPhone's Secure Element, an industry-standard, hardware-isolated chip designed to store sensitive payment credentials. During a Tap to Cash exchange:

• Tokenized Data: The devices do not transmit actual bank account details, card numbers, or full Apple Account identifiers. Instead, they share cryptographically generated tokens to validate the transfer request.
• Privacy Protection: Unlike traditional peer-to-peer payment apps or standard Apple Messages transfers, no personal contact details (such as names, phone numbers, or email addresses) are visible to the counterparty, preserving user anonymity.

Transaction Finalization via Apple Cash

Once the receiving iPhone accepts the transfer—which may also require biometric confirmation from the recipient—the cryptographically signed payload is sent to Apple's payment infrastructure. Apple Cash processes the ledger adjustment, moving the funds from the sender's balance to the recipient's balance over an encrypted network connection. A haptic tap and an on-screen visual confirmation alert both users that the transfer is complete.