Magcard Write Read Utility Program ((better)) ◉

TRACK_MAX_LEN = 1: 79, 2: 40, 3: 107 class MagCard: def init (self): self.track1 = "" self.track2 = "" self.track3 = ""

def read_track(self, track_num): if track_num == 1: return self.track1 elif track_num == 2: return self.track2 elif track_num == 3: return self.track3 else: raise ValueError("Track must be 1, 2, or 3")

#!/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:;<=>?") magcard write read utility program

if args.write or args.read: cli_mode(args) return

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

def interactive_read(card): track = int(input("Enter track to read (1/2/3): ")) data = card.read_track(track) if data: print(f"Track track raw data: data") # Show encoded version for realism encoded = encode_track(data) print(f"Track track encoded (with sentinels + checksum): encoded") # Verify decode decoded = decode_track(encoded) print(f"Decoded & verified: decoded") else: print(f"Track track is empty.") def cli_mode(args): card = MagCard() if args.write: try: track, data = args.write.split(':', 1) track = int(track) card.write_track(track, data) print(f"Written track track: data") except Exception as e: print(f"Error writing: e") if args.read: try: track = int(args.read) data = card.read_track(track) print(f"Track track: data if data else '<empty>'") except Exception as e: print(f"Error reading: e") --- Main interactive menu --- def main(): parser = argparse.ArgumentParser(description="Magnetic Card Read/Write Utility (simulated)") parser.add_argument("--write", help="Write track, format: track:data (e.g., 2:1234567890)") parser.add_argument("--read", help="Read track, e.g., --read 1") args = parser.parse_args()

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") | | Read/Write abstraction | Easy to replace

def decode_track(encoded): """Extracts raw data and verifies LRC""" if len(encoded) < 4: return None # Expected format: S data E checksum start_sentinel = encoded[0] end_sentinel = encoded[-2] checksum = encoded[-1] data_part = encoded[1:-2]