Before reading a sector, the reader must authenticate to the tag with a secret access key. More deatiled Information about this can be found in the following links: A Mifare Classic 1k tag contains 16 sectors.Įach of these sectors has 3 blocks of data storage and 1 block for storing the secret access keys and access controls.

Mifare Classic in general is stated insecure, because it’s encryption protocol has been cracked. There are also other types like the “Mifare Classic 4k” and the “Mifare Mini” each having a different memory size. The NFC tag I analyzed is a so called “Mifare Classic 1k” tag.ġk stands for the size of data the tag can store. You can also recharge your tag via the machine if you run out of credits. You can touch it with your tag to buy some drinks and the corresponding price is subtracted from the ammount stored on the tag. In this example the vending machine has an active NFC reader built in. This is usually used when sending data for example in “Android Beam”. There is also an active - active mode where both endpoints can send data and need to be powered seperately. It also powers the passive device via an electromagnetic field. The active device scans for the passive one and establishes a connection on contact. Basically there is an active NFC enabled device (the reader) and a passive device (the tag). NFC nowadays is used for access cards, public transport, some more and in this case: Vending Machines.

NFC stands for Near Field Communication and is used to communicate over short distances. At the end I show you how to reprogram a vending machine’s NFC tag to contain more credits. In this blog post I will cover some quick basics about NFC, Mifare Classic and how to set up everything for reading and writing a NFC tag. And event ticketing They serve as a perfect contactless replacement for magnetic stripe, barcode, or QR-code systems. MIFARE ® Ultralight-based tickets offer an ideal solution for low-cost, high-volume applications such as public transport, loyalty cards. If you manage to crack all the keys you can see the HEX encoded contents of the key on your terminal and.

Cracking mifare ultralight