Token Payments on Devices

Phones, smartwatches and tablets are now an ordinary way to pay. All of them rely on tokenization to do it safely.

How a device pays

Contactless payments use NFC (Near-Field Communication), a set of protocols that lets two devices exchange data over a distance of about four centimetres or less. One device is the phone or watch; the other is an NFC-enabled point-of-sale terminal.

The device stores the payment credential in a Secure Element, a dedicated microprocessor that holds the cardholder's data and performs the cryptographic work. At the moment of purchase, the Secure Element emulates a contactless card using standard industry protocols, and the terminal authorizes the transaction as if a physical card had been tapped.

Depending on the wallet and the device, the credential lives either in a physical embedded Secure Element (token type S) or in cloud-based storage with keys replenished online (token type C). Both are contactless; the difference is where the keys are held. Your integration does not change between them.

Why the token matters here

Consider a cardholder adding a card to Apple Pay.

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sequenceDiagram
    autonumber
    participant CH as Cardholder
    participant D as Device / Wallet
    participant MC as Mastercard MDES
    participant UDT as UnDosTres

    CH->>D: Adds the card
    D->>MC: Requests a token for this PAN
    MC->>UDT: Asks whether this card may be tokenized
    UDT-->>MC: Approves
    MC->>MC: Creates the token, stores the PAN in the vault
    MC-->>D: Returns the token
    Note over D: The device now holds a token. It never holds the PAN.

From that point on, the device pays with the token. If the phone is compromised, or a merchant is breached, what leaks is a number that only works on that one device, and that you can kill from your own systems without touching the card.

This is the practical benefit to state to your risk team: a tokenized card can lose a device without losing the card. The cardholder deletes the token from the phone, or you delete it, and the physical card keeps working.

What this means for your integration

Nothing, at payment time. Device payments arrive on the same authorization interface as any other transaction. What you do have to build is:

• getting the token created — Provisioning Overview
• keeping its state right — Token Lifecycle Management

Related

• How Token Processing Works — the authorization path, step by step
• Tokenization Overview — roles and terminology