#!/usr/bin/env python3 """ Magnetic Card Read/Write Utility (Simulated / Educational) Supports ISO 7811 tracks 1, 2, 3. """ import re import argparse TRACK1_CHARSET = set("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 .-+/$%*") TRACK2_CHARSET = set("0123456789:;<=>?") TRACK3_CHARSET = set("0123456789:;<=>?")
For real hardware (e.g., MagTek, ID Tech readers), you would replace the simulated I/O with serial/USB HID commands.
def clear(self): self.track1 = "" self.track2 = "" self.track3 = "" def encode_track(data, start_sentinel='%', end_sentinel='?'): """Adds start/end sentinels and LRC (simple XOR checksum)""" lrc = 0 for ch in data: lrc ^= ord(ch) checksum_char = chr(lrc % 128) # simple printable approximation return f"start_sentineldataend_sentinelchecksum_char" magcard write read utility program
For example, a USB keyboard wedge reader would just capture swiped data as if typed – no special driver needed. A writer would require sending track data in a proprietary command format over USB HID or serial.
# Verify checksum calc_lrc = 0 for ch in data_part: calc_lrc ^= ord(ch) if chr(calc_lrc % 128) != checksum: raise ValueError("Checksum mismatch – possible read error") return data_part def display_card(card): print("\n=== CURRENT CARD DATA ===") print(f"Track 1: card.track1 if card.track1 else '<empty>'") print(f"Track 2: card.track2 if card.track2 else '<empty>'") print(f"Track 3: card.track3 if card.track3 else '<empty>'") print("=========================\n") A writer would require sending track data in
python magcard_util.py --read 1 | Feature | Description | |--------|-------------| | ISO 7811 compliance | Enforces valid character sets and max lengths per track. | | Sentinel & LRC | Simulates magnetic stripe encoding with start/end sentinels and XOR checksum. | | Read/Write abstraction | Easy to replace MagCard class with real hardware driver (serial/HID). | | Error handling | Prevents invalid data from being written. | Extending to real hardware To use actual magnetic stripe readers/writers (e.g., MagTek, IDTECH, HID Omnikey), replace the MagCard class methods with device-specific commands – typically via serial or pyusb .
TRACK_MAX_LEN = 1: 79, 2: 40, 3: 107 class MagCard: def init (self): self.track1 = "" self.track2 = "" self.track3 = "" | | Read/Write abstraction | Easy to replace
def write_track(self, track_num, data): if not self.is_valid_track(track_num, data): raise ValueError(f"Invalid data for track track_num. Length or character mismatch.") if track_num == 1: self.track1 = data elif track_num == 2: self.track2 = data elif track_num == 3: self.track3 = data else: raise ValueError("Track must be 1, 2, or 3")
