git.zerfleddert.de Git - proxmark3-svn/blob - tools/mfkey/mfkey64.c

   1 #define __STDC_FORMAT_MACROS
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <time.h>
   5 #include <inttypes.h>
   6 #include "crapto1.h"
   7
   8 int main (int argc, char *argv[]) {
   9         struct Crypto1State *revstate;
  10         uint64_t key;     // recovered key
  11         uint32_t uid;     // serial number
  12         uint32_t nt;      // tag challenge
  13         uint32_t nr_enc;  // encrypted reader challenge
  14         uint32_t ar_enc;  // encrypted reader response
  15         uint32_t at_enc;  // encrypted tag response
  16         uint32_t ks2;     // keystream used to encrypt reader response
  17         uint32_t ks3;     // keystream used to encrypt tag response
  18
  19         printf("MIFARE Classic key recovery - based 64 bits of keystream\n");
  20         printf("Recover key from only one complete authentication!\n\n");
  21
  22         if (argc < 6) {
  23                 printf(" syntax: %s <uid> <nt> <{nr}> <{ar}> <{at}> [enc...]\n\n", argv[0]);
  24                 return 1;
  25         }
  26
  27         int encc = argc - 6;
  28         int enclen[encc];
  29         uint8_t enc[encc][120];
  30
  31         sscanf(argv[1],"%x",&uid);
  32         sscanf(argv[2],"%x",&nt);
  33         sscanf(argv[3],"%x",&nr_enc);
  34         sscanf(argv[4],"%x",&ar_enc);
  35         sscanf(argv[5],"%x",&at_enc);
  36         for (int i = 0; i < encc; i++) {
  37                 enclen[i] = strlen(argv[i + 6]) / 2;
  38                 for (int i2 = 0; i2 < enclen[i]; i2++) {
  39                         sscanf(argv[i+6] + i2*2, "%2x", (unsigned int *)&enc[i][i2]);
  40                 }
  41         }
  42
  43         printf("Recovering key for:\n");
  44
  45         printf("  uid: %08x\n",uid);
  46         printf("   nt: %08x\n",nt);
  47         printf(" {nr}: %08x\n",nr_enc);
  48         printf(" {ar}: %08x\n",ar_enc);
  49         printf(" {at}: %08x\n",at_enc);
  50
  51         for (int i = 0; i < encc; i++) {
  52                 printf("{enc%d}: ", i);
  53                 for (int i2 = 0; i2 < enclen[i]; i2++) {
  54                         printf("%02x", enc[i][i2]);
  55                 }
  56                 printf("\n");
  57         }
  58
  59         // Generate lfsr succesors of the tag challenge
  60         printf("\nLFSR succesors of the tag challenge:\n");
  61         printf("  nt': %08x\n",prng_successor(nt, 64));
  62         printf(" nt'': %08x\n",prng_successor(nt, 96));
  63
  64         clock_t t1 = clock();
  65
  66         // Extract the keystream from the messages
  67         printf("\nKeystream used to generate {ar} and {at}:\n");
  68         ks2 = ar_enc ^ prng_successor(nt, 64);
  69         ks3 = at_enc ^ prng_successor(nt, 96);
  70         printf("  ks2: %08x\n",ks2);
  71         printf("  ks3: %08x\n",ks3);
  72
  73         revstate = lfsr_recovery64(ks2, ks3);
  74
  75         // Decrypting communication using keystream if presented
  76         if (argc > 6 ) {
  77                 printf("\nDecrypted communication:\n");
  78                 uint8_t ks4;
  79                 int rollb = 0;
  80                 for (int i = 0; i < encc; i++) {
  81                         printf("{dec%d}: ", i);
  82                         for (int i2 = 0; i2 < enclen[i]; i2++) {
  83                                 ks4 = crypto1_byte(revstate, 0, 0);
  84                                 printf("%02x", ks4 ^ enc[i][i2]);
  85                                 rollb += 1;
  86                         }
  87                         printf("\n");
  88                 }
  89                 for (int i = 0; i < rollb; i++)
  90                         lfsr_rollback_byte(revstate, 0, 0);
  91         }
  92
  93         lfsr_rollback_word(revstate, 0, 0);
  94         lfsr_rollback_word(revstate, 0, 0);
  95         lfsr_rollback_word(revstate, nr_enc, 1);
  96         lfsr_rollback_word(revstate, uid ^ nt, 0);
  97         crypto1_get_lfsr(revstate, &key);
  98         printf("\nFound Key: [%012" PRIx64 "]\n\n", key);
  99         crypto1_destroy(revstate);
 100
 101         t1 = clock() - t1;
 102         if ( t1 > 0 ) printf("Time : %.0f ticks \n", (float)t1);
 103         return 0;
 104 }