Hello @asaf_shpigler, Good Day!
Thank you for your interest in our products.
You may find a guide on how to set a password protection for NTAG21x using the TagWriter app in section 5 of the TagWriter User Manual, however, please keep in mind that the password protection available in TagWriter will set the dataset on your tag in read-only mode, the tag cannot be overwritten without entering the password, but it still can be read without password authentication.
If you want to prevent the tag from being read without entering the password, you would need to set the PROT bit of the tag, which defines the r/w memory protection. This process can be performed using our recommended RFIDDiscover Software application, which is a tool that is meant to be used with the PEGODA Contactless Smart Card Reader And offers an easy way of exploring the NTAG21x and other smart cards' features.
Please consider that in order to have access to the tool you would need to sign an NDA since this software is part of NXP's secure resources.
My best regards,
Daniel
