Investigating nfc cards

Investigating Mifare NFC cards with PN532 module and C.H.I.P

In this brief document i will attempt to explain how to setup your chip and pn532 NFC reader to poke around with NFc cars.

Setup

After flashing[1] your chip, first thing yo need to do is install libnfc by running command

apt-get install libnfc-bin

And add your NFC device

mkdir -p /etc/nfc/devices.d/
echo -e "name = \"PN532 board via UART\" \nconnstring = pn532_uart:/dev/ttyS0" > /etc/nfc/devices.d/pn532_uart.conf

Now you actually need to connect reader to chip. Check attached picture to see where to connect each pin.

If you did everything right, you should be able to detect the device by running

nfc-scan-device

Identifying cards

Using this command you can check if reader detects NFC card successfully

nfc-list

You can identify cards by returned ATQA/SENS_RES, SAK/SEL_RES and ATS[2] bytes manually by useing command

nfc-list

or you can use this utility[3] to make it easier. Below you can see responses from ISIC card (non bank issued one).

• 
  lsnfc output
• 
  nfc-list output

Basic working principles of Mifare Classic card

Both, ISIC and Estonian transportation cards are working on Mifare Classic chip. Bank cards use another chip which is able to emulate Mifare Classic. SEB uses Mifare Plus and Swedbank uses JCOP as far as i know.

Mifare classic`s memory is organized in 16 sectors of 4 blocks. One block contains 16 bytes.