topic MIFARE UID Byte Lengths in NFC

MIFARE UID Byte Lengths

andrewvillagran — Wed, 13 Nov 2019 18:00:14 GMT

Hi, a client wants me to purchase 26-bit MIFARE DESFire cards, but I'm not sure if that's even a thing. I've been reviewing this document: https://www.nxp.com/docs/en/application-note/AN10833.pdf (page 9), and it appears that each card format has a 4 or 7 byte portion for the UID (i.e. 32 or 56 bits), plus an extra portion of bytes for proprietary data. For the UID, is it always 32 or 56 bits, or is there such a thing as 26-bit or 34-bit? Also, is this the best document to use to understand the different MIFARE card formats, or is there something better?

Re: MIFARE UID Byte Lengths

Jonathan_Iglesias — Thu, 21 Nov 2019 22:11:17 GMT

Hi Andrew Villagran,

as you may know the ISO 14443 cards can be found in 3 types of UID

and about the card form factors, it is important to mention that NXP does not sell the full card solution, by this I mean IC + Antenna + wrapper we sell the IC inside the card, we have a list of manufacturers that can help you with this solutions using NXP ICs.

RFID Ecosystem | NXP

Registered Partner | MIFARE

Have a great day !

Jonathan

Re: MIFARE UID Byte Lengths

sb2 — Fri, 06 Mar 2020 09:58:05 GMT

Dear Andrew

What your customer is looking for is most likely a card reader that will output 26 bit wiegand data when reading a DESFire card.

There are 2 ways for this to work:

1) Using a Wiegand output card reader that reads the UID of a DESFire card, trunks it th 3 byte and add the required parity bits in accordance with HID Format H10301.

2) Using a Wiegand output card reader that reads data from a DESFire file (in an application) that is encoded with card data in wiegand 26 bit format (H10301).

Your customer may not be using the 26 bit format on a non wiegand reader (OSDP interface perhaps?)

Regards

Søren