how to set Password to ntag215/213? and how to authenticate after password set ..?what is the use of PACK?

Question

i want to make an app in react native to write/read nfc tag with password protection for write operation only i prefered NFCTAG215 documentation i have idea about page address and byte present in ntag215 architecture ....but didnt understanding how to set values in it ..... i prefer this example but dont know about PACK value and after setting pass to tag how to authenticate and and rewrite that card..pls help me ... enter image description here

Answer 1

I don't know the real reason the designers of the card included this but I can see the logic for including this when you have enabled password protection of reading from the card as well as writing.

If you have enabled password protection of reading then probably want to be able to trust that the read data is coming from a real password protected card and that if you are writing data that you don't want read without a password that you are not writing it to an insecure card.

This is because it would be easy to have a fake card/system that accepted any password without error and then your program would think it was a secure system and trust any reads from it and possible write sensitive data to the fake card/system where it can be seen without the password.

The PACK should be verified by the program against it's stored value, but less useful if you are only write protecting the card.