MiFare - Difference between UID and Serial Number of MiFare Card

Question

I need to read serial number of MiFare card usin WinSCard. I am able to read 7B UID from the MiFare card.

The confusion is that i dont know if the UID and the serial number of MiFare card are same?!!

I have googled the issue but only could get partial success. I found a question on stackoverflow also but it did not help.

I found a document of NXP online which says UID and serial number are different. (on page number 3, line number 5)

There is an application of OmniKey that reads the serial number of the card, and it also returns UID only.

NXP documentation says UID <> Serial Number and a other standard OmniKey application returns UID as Serial Number.

I have started pulling my hair off on the issue. I'd greatly appreciate if anyone could help.

Answer 1

The differentiation in this case comes from the fact that a "Serial Number" implies that the numbers are a series, thus sequentially assigned.

MIFARE cards have Unique Identification Numbers (or in short UID), which are generated by an internal rule which is not necessarily sequential. This means that if you see a card with UID 01020304050607 it does not mean that there are at least that many cards produced so far.

If you ever see someone referring to the Card Serial Number, they are in fact referring to the UID.

The only last confusion can come from the fact that MIFARE cards can be configured to return Random IDs during activation. If that is the case, you would get different "UID" each time you activate the card. In that scenario you need to read the data contained in Block 0 (for which you will need to know the key to sector 0) to get the real UID of the card.