Example usage of pyscard to read and write second sector of xSiiD with password protection turned on.

nfc-example.py

#!/usr/bin/env python3
from smartcard.System import readers
from smartcard.CardRequest import CardRequest
from smartcard.Exceptions import CardRequestTimeoutException, CardConnectionException
import time


reader = readers()
conn =  reader[0].createConnection()

accepted_cards = {
    # card id(s) goes here
    b'\x00\x00\x00\x00\x00\x00\x00'
}

class CardError(Exception):
    def __init__(self, data):
        self.data = data

    def __repr__(self):
        return f"CardError: Failed with data: {self.data}"

def send_data(conn, data, expected_code=0):
    try:

        payload = [0xFF, 0x00, 0x00, 0x00, len(data) + 2, 0xD4, 0x42] + data
        data, sw1, sw2 = conn.transmit(payload)
        if sw1 != 0x90 or sw2 != 0:
            raise Exception(f"Failed with code: {sw1} {sw2}")
        if data[0] == 213 and data[1] == 67 and data[2] == expected_code:
            return data[3:]
        else:
            raise CardError(data)
    except CardConnectionException as ex:
        if str(ex) != "Card returned no valid response: Command successful. (0x00000000)":
            raise
        return None

while True:
    cardrequest = CardRequest(timeout=1)
    try:
        cardrequest.waitforcard()
        conn.connect()
        result, sw1, sw2 = conn.transmit([0xFF, 0xCA, 0x00, 0x00, 0x00])
        if bytes(result) in accepted_cards:
            print("Accepted card detected.")
        else:
            continue

        try:
            # last 4 bytes in command are password
            pwack = send_data(conn, [0x1B, 0x00, 0x00, 0x00, 0x00])
            # two bytes here are pwack, which is only given with right password
            if bytes(pwack) != b'\x00\x00':
                print("Invalid PW ACK, could be tamper attempt.")
                break
        except CardError as ex:
            if ex.data[2] == 1:
                print("Password auth interrupted.")
                continue
            print("Password auth failed, could be tamper attempt.")
            break

        # select sector 2
        send_data(conn, [0xC2, 0xFF], expected_code=2)
        send_data(conn, [0x01, 0x00, 0x00, 0x00], expected_code=1)

        # to write data
        #send_data(conn, [0xA2, 0] + list(bytearray.fromhex("00000000")), expected_code=2)
        #send_data(conn, [0xA2, 1] + list(bytearray.fromhex("00000000")), expected_code=2)
        #send_data(conn, [0xA2, 2] + list(bytearray.fromhex("00000000")), expected_code=2)
        #send_data(conn, [0xA2, 3] + list(bytearray.fromhex("00000000")), expected_code=2)

        # read k, which is first 16 bytes of sector 2
        k = bytes(send_data(conn, [0x30, 0]))

        # do something with k

        time.sleep(5)
    except CardRequestTimeoutException:
        pass
    except Exception as ex:
        import traceback
        traceback.print_exc()