Issue while authenticate tag with predefined password for NTAG213

[AR-2195]

Hello all. I am Wan Ammar

Referring to the above topic, I cannot authenticate the tag which is the NTAG213 using the PWD_AUTH command. 

The flow of the program that has been built:

1. the program send a file to the tag 

2. the program then set a password to the tag in Block 2

3. the program verifies the sent file comparing it with the original file

In order to verify the tag, the program got to have the password.

When running the program, I have logged the password for being sent and stored, and it is different:

Stored password Block 2: 00050000
Password being sent:31323334

can someone explain this to me?

[teresa32yon · Accepted solution]

Hi Wan Ammar! It sounds like you're having an issue with the password authentication for your NTAG213 tag. Let's try to figure this out together.

From your description, it seems there's a discrepancy between the stored password and the password being sent during the authentication process. Here are a few things to check:

1. Password Format: Ensure that the password is correctly formatted and stored in the tag. The password should be in hexadecimal format. For example, the password 31323334 should be stored as 0x31323334.

2. Command Sequence: Verify that the command sequence for setting the password and performing the authentication is correct. Here's a typical sequence for setting the password and authenticating:

   • Set Password: FF D6 00 2B 04 31 32 33 34

   • Set PACK: FF D6 00 2C 04 00 00 00 00

   • Activate AUTH0: FF D6 00 29 04 04 00 00 00

   • Authenticate: FF 00 00 1B 31 32 33 34

3. Memory Block: Ensure that the password is stored in the correct memory block (Block 2 in your case).

4. Command Structure: Double-check the command structure and ensure that the correct APDU commands are being sent. The PWD_AUTH command should look like this:

   • PWD_AUTH Command: FF 00 00 1B 31 32 33 34

5. Reader Compatibility: Make sure that your reader is compatible with the NTAG213 and that it supports the PWD_AUTH command.