Create MagSpoofPI.c

MagSpoofPI.c

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+/*
+ * MagSpoof - "wireless" magnetic stripe/credit card emulator
+ *
+ * by Samy Kamkar
+ *
+ * http://samy.pl/magspoof/
+ *
+ * - Allows you to store all of your credit cards and magstripes in one device
+ * - Works on traditional magstripe readers wirelessly (no NFC/RFID required)
+ * - Can disable Chip-and-PIN (code not included)
+ * - Correctly predicts Amex credit card numbers + expirations from previous card number (code not included)
+ * - Supports all three magnetic stripe tracks, and even supports Track 1+2 simultaneously
+ * - Easy to build using Arduino or ATtiny
+ *
+ *----------------------------------------------------------
+ *
+ * MagSpoofPI - code integration by Salvador Mendoza
+ *
+ * Main idea: be able to compile MagSpoof with variable tracks, and use MagSpoof
+ * without arduino dependency, and be able to use it without removing it from 
+ * the raspberry pi gpio.
+ * -
+ * Special code for Raspberry Pi implementing avr-gcc without arduino.
+ * -
+ * Main modifications from the original MagSpoof in functions like digitalWrite(), 
+ * setup() and loop().
+ *
+ * Example of configuration:
+ * rbpi - Resistor - attiny85
+ *  19  ->  1k  -->  PB0
+ *  21  ->  1k  -->  PB1
+ *  23  ->  1k  -->  PB2
+ * DC17 ->  n/a -->  VCC
+ * GND20 -> n/a -->  GND
+ *  15  --> 1k  -->  PB5
+ * Any other pin to enable/disable MagSpoof after be compiled
+ * That pin has to be True before "make install" GPIO.setup(pin, 1)
+ * pin --> 10k -->     PB2
+ * GND > to same 10k > PB2
+ */
+
+
+#include <avr/io.h>
+#include <util/delay.h>
+#include <avr/interrupt.h>
+#include <avr/sleep.h>
+#define interrupts() sei()
+#define noInterrupts() cli()
+#define PIN_A PB0
+#define PIN_B PB1
+#define BUTTON_PIN PB4
+#define ENABLE_PIN PB3 // also green LED
+#define SWAP_PIN PB2 // unused
+#define CLOCK_US 200
+#define HIGH 1
+#define LOW 0
+#define _BV(bit) (1 << (bit))
+
+#define BETWEEN_ZERO 53 // 53 zeros between track1 & 2
+
+#define TRACKS 2
+
+// consts get stored in flash as we don't adjust them
+const char* tracks[] = {
+"%4059557240058686^22111015312020010591?;4059557240058686^22111015312020010591?\0", // Track 1
+";4059557240058686=22111015312020010591?\0" // Track 2
+};
+
+char revTrack[41];
+const int sublen[] = { 
+  32, 48, 48 };
+
+const int bitlen[] = { 
+  7, 5, 5 };
+
+unsigned int curTrack = 0;
+
+void digitalWrite(int a, int b){
+    if (b == 1) {
+        PORTB |= (1<<a); // high
+    }else if (b == 0){
+        PORTB &= ~(1<<a); // low
+    }else {
+        PORTB &= ~(b<<a); // Anything else
+    }
+}
+void blink(int pin, int times)
+{
+  int i;
+  for (i = 0; i < times; i++)
+  {
+    //PORTB = 0b00001000; 
+    digitalWrite(pin, HIGH);
+    _delay_ms(200);
+    digitalWrite(pin, LOW);
+    _delay_ms(200);
+    //PORTB = 0b00000000; 
+  }
+}
+// stores track for reverse usage later
+void storeRevTrack(int track)
+{
+  int i, j, tmp, crc, lrc = 0;
+  track--; // index 0
+  int dir = 0;
+
+  for (i = 0; tracks[track][i] != '\0'; i++)
+  {
+    crc = 1;
+    tmp = tracks[track][i] - sublen[track];
+
+    for (j = 0; j < bitlen[track]-1; j++)
+    {
+      crc ^= tmp & 1;
+      lrc ^= (tmp & 1) << j;
+      tmp & 1 ?
+        (revTrack[i] |= 1 << j) :
+        (revTrack[i] &= ~(1 << j));
+      tmp >>= 1;
+    }
+    crc ?
+      (revTrack[i] |= 1 << 4) :
+      (revTrack[i] &= ~(1 << 4));
+  } 
+
+  // finish calculating and send last "byte" (LRC)
+  tmp = lrc;
+  crc = 1;
+  for (j = 0; j < bitlen[track]-1; j++)
+  {
+    crc ^= tmp & 1;
+    tmp & 1 ?
+      (revTrack[i] |= 1 << j) :
+      (revTrack[i] &= ~(1 << j));
+    tmp >>= 1;
+  }
+  crc ?
+    (revTrack[i] |= 1 << 4) :
+    (revTrack[i] &= ~(1 << 4));
+
+  i++;
+  revTrack[i] = '\0';
+}
+void setup()
+{
+  //DDRB = 0b00001111;
+  DDRB |= (1 << PIN_A); // output
+  DDRB |= (1 << PIN_B); // output
+  DDRB |= (1 << ENABLE_PIN); // output
+  DDRB &=~(1 << BUTTON_PIN); // input
+  PORTB |= (1<<BUTTON_PIN); // high to use it like INPUT_PULLUP
+
+  // blink to show we started up
+  blink(ENABLE_PIN, 3);
+  //store reverse track 2 to play later
+  storeRevTrack(2);
+}
+
+
+// send a single bit out
+int dir;
+void playBit(int sendBit)
+{
+  dir ^= 1;
+  digitalWrite(PIN_A, dir);
+  digitalWrite(PIN_B, !dir);
+  _delay_us(CLOCK_US);
+
+  if (sendBit)
+  {
+    dir ^= 1;
+    digitalWrite(PIN_A, dir);
+    digitalWrite(PIN_B, !dir);
+  }
+  _delay_us(CLOCK_US);
+
+}
+
+// when reversing
+void reverseTrack(int track)
+{
+  int i = 0;
+  track--; // index 0
+  dir = 0;
+  int j;
+  while (revTrack[i++] != '\0');
+  i--;
+  while (i--)
+    for (j = bitlen[track]-1; j >= 0; j--)
+      playBit((revTrack[i] >> j) & 1);
+}
+
+// plays out a full track, calculating CRCs and LRC
+void playTrack(int track)
+{
+  int tmp, crc, lrc = 0;
+  track--; // index 0
+  dir = 0;
+
+  // enable H-bridge and LED
+  digitalWrite(ENABLE_PIN, HIGH);
+
+  // First put out a bunch of leading zeros.
+  int i, j;
+  for (i = 0; i < 25; i++)
+    playBit(0);
+
+  // Check for the end of the track
+  for (i = 0; tracks[track][i] != '\0'; i++)
+  {
+    crc = 1;
+    tmp = tracks[track][i] - sublen[track];
+
+    for (j = 0; j < bitlen[track]-1; j++)
+    {
+      crc ^= tmp & 1;
+      lrc ^= (tmp & 1) << j;
+      playBit(tmp & 1);
+      tmp >>= 1;
+    }
+    playBit(crc);
+  }  
+
+  // finish calculating and send last "byte" (LRC)
+  tmp = lrc;
+  crc = 1;
+  for (j = 0; j < bitlen[track]-1; j++)
+  {
+    crc ^= tmp & 1;
+    playBit(tmp & 1);
+    tmp >>= 1;
+  }
+  playBit(crc);
+
+  // if track 1, play 2nd track in reverse (like swiping back?)
+  if (track == 0)
+  {
+    // if track 1, also play track 2 in reverse
+    // zeros in between
+    for (i = 0; i < BETWEEN_ZERO; i++)
+      playBit(0);
+
+    // send second track in reverse
+    reverseTrack(2);
+  }
+
+  // finish with 0's
+  for (i = 0; i < 5 * 5; i++)
+    playBit(0);
+
+  digitalWrite(PIN_A, LOW);
+  digitalWrite(PIN_B, LOW);
+  digitalWrite(ENABLE_PIN, LOW);
+}
+
+
+void sleep()
+{
+  GIMSK |= _BV(PCIE);                     // Enable Pin Change Interrupts
+  PCMSK |= _BV(PCINT2);                   // Use PB3 as interrupt pin
+  ADCSRA &= ~_BV(ADEN);                   // ADC off
+  set_sleep_mode(SLEEP_MODE_PWR_DOWN);    // replaces above statement
+
+  MCUCR &= ~_BV(ISC01);
+  MCUCR &= ~_BV(ISC00);                   // Interrupt on rising edge
+  sleep_enable();                         // Sets the Sleep Enable bit in the MCUCR Register (SE BIT)
+  sei();                                  // Enable interrupts
+  sleep_cpu();                            // sleep
+
+  cli();                                  // Disable interrupts
+  PCMSK &= ~_BV(PCINT2);                  // Turn off PB3 as interrupt pin
+  sleep_disable();                        // Clear SE bit
+  ADCSRA |= _BV(ADEN);                    // ADC on
+
+  sei();                                  // Enable interrupts
+}
+
+// XXX move playtrack in here?
+ISR(PCINT0_vect) {
+  /*  noInterrupts();
+   while (digitalRead(BUTTON_PIN) == LOW);
+   
+   delay(50);
+   while (digitalRead(BUTTON_PIN) == LOW);
+   playTrack(1 + (curTrack++ % 2)); 
+   delay(400);
+   
+   interrupts();*/
+
+}
+
+
+void loop()
+{
+  sleep();
+  noInterrupts();
+  while ((PINB & (1<<BUTTON_PIN)) != 0);
+  _delay_ms(50);
+  while ((PINB & (1<<BUTTON_PIN)) != 0);
+  playTrack(1 + (curTrack++ % 2)); 
+  _delay_ms(400);
+
+  interrupts();
+  //playTrack(1 + (curTrack++ % 2));
+}
+int main(void){
+    setup();
+    while(1){
+        loop();
+    }
+    return 1;
+}