NTAG213 authentication

[1simone0]

Hi all,

Little description of my application:

Assume I have some NTAG213 protected by known password.

I'm developing an application on a NFC reader/writer and I would authenticate using PWD_AUTH command and, after that be able to write some datas (a byte is enough to start) somewhere in the TAG, assume page 6, and it's not important to use NDEF formatted messages because is just a byte usefull to say TAG OK or TAG not OK and only mine reader will read that information.

I'm having some issues probably due to my code trying to authenticate but I'm able to write the datas in not protected TAG, anyway it's not important actually and I have some dubts ...

My questions:

Does the TAG formatting status (and I mean NDEF formatted or default formatted) affect the behavior and so the approach to authenticate ?

I study pretty well the data sheet but it's not clear to me if I should append (maybe respecting a timeout) a read or write message to the authentication message every time I want to read or write something or after the first authentication I can just send normal read and write messages until the TAG is not removed from the reader field?

[Kan_Li]

Hi Simone,

Does the TAG formatting status (and I mean NDEF formatted or default formatted) affect the behavior and so the approach to authenticate ?

- No, it doesn't affect, it just affects the reader which only supports NDEF formatted TAG.

I study pretty well the data sheet but it's not clear to me if I should append (maybe respecting a timeout) a read or write message to the authentication message every time I want to read or write something or after the first authentication I can just send normal read and write messages until the TAG is not removed from the reader field?

- After the first successful authentication you can just send normal read and write messages until the TAG is not removed from the reader field.

Hope that makes sense,

Have a great day,
Kan

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