Help with Writing Data to MIFARE DESFire Card (OSS-SO) Using Python-DESFire and ACS ACR1281 1S Reade

[DiegoGuzman-37]

Hello everyone,

I’m new to developing access control applications and I’m currently experimenting with MIFARE DESFire cards for an OSS-SO-based project.

I’d like to understand whether it’s absolutely necessary to know the PICC (UID) and AID in advance to write data on the card — or if the AID should be created manually within my own application. My goal is to write and manage data using Python, specifically with the Python-DESFire library.

Right now, I’m facing a permissions issue that prevents me from writing to the card. I’m using an ACS ACR1281 1S Dual Reader, which is supposed to support MIFARE DESFire, but I can’t seem to get past the write access restrictions.

So, I have a few questions:

Is it mandatory to know or define the AID and PICC beforehand to perform write operations under the OSS-SO standard?

Could this issue be related to the reader itself? Is the ACR1281 1S suitable for this kind of development, or would you recommend a different reader model for DESFire and Python integration?

Any guidance, examples, or reader recommendations would be greatly appreciated.
Thank you in advance for your help!

[Fabian_R]

Hello, thank you for your interest in our products.

In order to fully understand MIFARE DESFire products, I have to recommend please check the respective documentation and specifications.

All our cards work under ISO14443-4 specification and, in order to start personalizing each tag, is necessary to select them by UID. There is a similar requirement for Application ID.

Is possible to use Python for writing and managing the data but, we don't have such tools. Ours are only based on C or a C# library.

Still, to access to information is required to sign an NDA. For further information, please take a look at our FAQ.

[DiegoGuzman-37]

Ok, thank you so much Fabian!

Where can I sign that NDA, and where can I find that libraries for C# or C?

[Fabian_R]

Hello sir,

I shared the FAQ link where you can find the NDA-form to sign. You need to create a new ticket for the NDA request.

After having your NDA active, you just need to request the documentation as described in this Guide: nxp-secure-files-user-guide.pdf