NFC chip reading

Tapping a passport or ID to read the chip inside it.

The person holds the document against the back of their phone, and the phone reads the electronic chip that stores the same details as the printed page.

Contactless read of an ePassport or eID chip, verifying the issuer's digital signature over the stored data group. Near-field communication (NFC) is the short-range wireless technology that lets a phone talk to the chip, and a data group is a block of stored information, such as the holder's details or photo.

A chip read typically follows these steps:

1. The app uses details from the document, such as the number from the machine-readable zone, to unlock the chip through an access protocol.
2. It reads the stored data groups, including the holder's details and facial photo.
3. It checks the issuer's digital signature, a step called passive authentication, using certificates from the issuing country.
4. Where the chip supports it, it runs a check that detects cloned chips.

The checks do different jobs:

• Access control, through protocols named Basic Access Control (BAC) and its successor PACE, keeps the chip from giving up data to anyone who simply scans it.
• Passive authentication confirms that the data was signed by the issuer and has not changed.
• Clone detection, through Active Authentication or Chip Authentication, confirms that the data came from an authentic chip and not a copy.

NFC chip reading sits next to terms that are easy to mix up:

• Machine-readable zone is the printed text that is often used to unlock the chip.
• Document verification inspects the visible document, while chip reading checks cryptographic data.
• Government-issued ID is the document that carries the chip.

For more, see What is a Biometric Passport or e-Passport?