boltcard/docs/CARD_PRIVACY.md

Card Privacy

Brief

The link that is programmed into the card and returned as the NDEF consists of three parts.

1. The static part
2. The encrypted part
3. The authentication part

lnurlw://yourdomain.com/ln?p=012345&c=6789  example

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^      ^^^      static

                             ^^^^^^         encrypted
                             
                                      ^^^^  authentication

Uses of the parts are as follows:

part	use
static	specfying the protocol and service location as a URI
encrypted	unique id and counter values encrypted by the card
authentication	a value to authenticate that the entire URI is as generated by the card

NXP NTAG424DNA features

Implementation