How MIFARE Uses Cookies

[Andreas Schmidt]

Hi.

We know all (or not) about these security features and we are sure that the sensitive data on the cards are read only. We don't know which data used for open a door. Bu we know that we are using the UID of the Card to identify the user who wants to raise his credit für printing ... at least until today. Now, the Reader of the pay terminal reads a wrong value that does not correspond with the entry in our database. He shoud read a ‭804CC0227D4204‬(hex), but reads ‭22C40EFD‬ (hex).
So we have to raise up their credits manually, which takes a lot time.

Thanks for all your help and patience.
Andreas

---

+ 0  |  - 0

[Andreas Schmidt]

The students get their cards fully configured and we get the UID (or whatever) from our IT-Service Center and fill up the database of our Software. When a student wants to enhance his value and use our pay terminal, this ID is used to authenticate the user. It works fine with the older cards for many years, but now ...???

These cards are used for open doors and go to the mensa also, so i think they don't use a random ID, but i really don't know.

Andreas

---

+ 0  |  - 0

[Andreas Schmidt]

Hello.

Yes, we know that. The UID of the new card is 7 bytes long, UID of the older cards only 4 bytes. That is no problem for our print solution, only the terminal to pay money to enhance the value of their print accounts does not read the UID exactly. We thought we can translate the 17 digits of the 7 bytes UID in 10 digits like the older Cards, so described here: https://www.nxp.com/docs/en/application-note/AN10927.pdf (3.3.2)

Is that a possible way?

Thanks
Andreas

---

+ 0  |  - 0

[Author]

Posts