ARTICLE AD BOX
I am developing an Android application that writes data to an NFC NTAG213 tag and I want to enable password protection so that the tag cannot be modified without authentication.
I am using Android’s NfcA technology to communicate with the tag. Writing and reading data works correctly, but I am confused about the correct sequence and configuration required to enable password protection using PWD_AUTH, PACK, and the ACCESS bytes.
What I have tried so far:
Writing the 4-byte password to the PWD page
Writing a 2-byte PACK value
Modifying the ACCESS byte to protect write operations
However, after writing these values, either:
The tag still allows writes without authentication, or
The tag becomes inaccessible until removed and re-tapped
I am unsure about:
Which pages must be written for NTAG213 password protection
The correct bit configuration of the ACCESS byte
Whether PWD_AUTH must be executed before every write operation on Android
Any Android-specific limitations when authenticating NTAG213 tags
Is there a recommended sequence or example for correctly enabling and testing password protection on NTAG213 using Android NFC?
