The strongest authenticity signal a dynamic NFC tag can give is proof that it is live — that a real, working tag is present right now, not a copy of one tap captured earlier.
TAGBASE establishes that with two scans:
- First scan records the item as seen and puts the verification into a pending state.
- Second scan asks the tag to prove itself again. A genuine tag produces new proof, so the verification becomes valid. A copy can only replay the proof it captured once, so it cannot pass the second scan and the verification is marked invalid.
The second scan is the liveness check. It is what separates a genuine item from a static copy, and it is why two-scan verification is the default.
One-step verification
A solution can choose a one-step experience that acts on the first scan, trading the second-scan liveness guarantee for a simpler tap. (In API terms, that’s never sending the second scan — see Verifications.) It’s available, but two-scan is recommended wherever authenticity matters.