How to re-enable full tag usage after a NFC brute force attack on password via i2c ?

[fleettech]

Hello, i'm currently working with NT3H2111 tag. I our use case, tags will be exposed to brute fore attack,  so i have set PWD,PACK and AUTHLIM value. When AUTHLIM number of invalid password is reached, even a valid password cannot unlock the device.

But, in my case i want (via i2c) to re-enable (after one hours) that a valid password unlock the device.

I have try to re-set  PWD,PACK and AUTHLIM to others value and then set again to valid value but it didn't work.

The only methods working i have foudn to reset NEG_AUTH_REACHED seem to be setting AUTHLIM=0 and sending valid password via NFC.

I can't use this solutions in final product.

Can you tell me is there's another way to reset internal counter or NEG_AUTH_REACHED bit via I2C access only ?

Thanks for your idea

[Jorge_Gonzalez]

Hello Eric PENNAMEN,

The limit on negative verification attempts can only be disabled before the maximum number is reached. After reaching the limit the protection is permanent and the protected memory is no longer accessible. This security mechanism cannot be reset as you intend to do.

Best Regards!,
Jorge Gonzalez

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------