# 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