Apple Enhanced Contactless Polling (ECP)

Apple's proprietary contactless protocol that adds a control-channel layer above standard ISO 14443 / NFC tap interactions. ECP lets the reader signal to the Apple device which credential type and which authentication mode (Express, TRA, biometric) the reader expects before the credential is presented.

Operationally, ECP is what enables 2FA-at-reader scenarios in Apple Wallet — the reader can require Two-factor Reader Authentication (TRA) or biometric confirmation as a condition of credential presentation, while still supporting Express Mode for low-friction flows.

Wavelynx, HID, and other reader manufacturers must implement ECP to support Apple Wallet credentials. Different ECP frame variants signal different credential families (transit, access, identity).