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 #define llx PRIx64
   9 #define lli PRIi64
  10
  11 int main (int argc, char *argv[]) {
  12         struct Crypto1State *revstate;
  13         uint64_t key;     // recovered key
  14         uint32_t uid;     // serial number
  15         uint32_t nt;      // tag challenge
  16         uint32_t nr_enc;  // encrypted reader challenge
  17         uint32_t ar_enc;  // encrypted reader response
  18         uint32_t at_enc;  // encrypted tag response
  19         uint32_t ks2;     // keystream used to encrypt reader response
  20         uint32_t ks3;     // keystream used to encrypt tag response
  21
  22         printf("MIFARE Classic key recovery - based 64 bits of keystream\n");
  23         printf("Recover key from only one complete authentication!\n\n");
  24
  25         if (argc < 6) {
  26                 printf(" syntax: %s <uid> <nt> <{nr}> <{ar}> <{at}> [enc...]\n\n", argv[0]);
  27                 return 1;
  28         }
  29
  30         int encc = argc - 6;
  31         int enclen[encc];
  32         uint8_t enc[encc][120];
  33
  34         sscanf(argv[1],"%x",&uid);
  35         sscanf(argv[2],"%x",&nt);
  36         sscanf(argv[3],"%x",&nr_enc);
  37         sscanf(argv[4],"%x",&ar_enc);
  38         sscanf(argv[5],"%x",&at_enc);
  39         for (int i = 0; i < encc; i++) {
  40                 enclen[i] = strlen(argv[i + 6]) / 2;
  41                 for (int i2 = 0; i2 < enclen[i]; i2++) {
  42                         sscanf(argv[i+6] + i2*2, "%2x", (unsigned int *)&enc[i][i2]);
  43                 }
  44         }
  45
  46         printf("Recovering key for:\n");
  47
  48         printf("  uid: %08x\n",uid);
  49         printf("   nt: %08x\n",nt);
  50         printf(" {nr}: %08x\n",nr_enc);
  51         printf(" {ar}: %08x\n",ar_enc);
  52         printf(" {at}: %08x\n",at_enc);
  53
  54         for (int i = 0; i < encc; i++) {
  55                 printf("{enc%d}: ", i);
  56                 for (int i2 = 0; i2 < enclen[i]; i2++) {
  57                         printf("%02x", enc[i][i2]);
  58                 }
  59                 printf("\n");
  60         }
  61
  62         // Generate lfsr succesors of the tag challenge
  63         printf("\nLFSR succesors of the tag challenge:\n");
  64         printf("  nt': %08x\n",prng_successor(nt, 64));
  65         printf(" nt'': %08x\n",prng_successor(nt, 96));
  66
  67         clock_t t1 = clock();
  68
  69         // Extract the keystream from the messages
  70         printf("\nKeystream used to generate {ar} and {at}:\n");
  71         ks2 = ar_enc ^ prng_successor(nt, 64);
  72         ks3 = at_enc ^ prng_successor(nt, 96);
  73         printf("  ks2: %08x\n",ks2);
  74         printf("  ks3: %08x\n",ks3);
  75
  76         revstate = lfsr_recovery64(ks2, ks3);
  77
  78         // Decrypting communication using keystream if presented
  79         if (argc > 6 ) {
  80                 printf("\nDecrypted communication:\n");
  81                 uint8_t ks4;
  82                 int rollb = 0;
  83                 for (int i = 0; i < encc; i++) {
  84                         printf("{dec%d}: ", i);
  85                         for (int i2 = 0; i2 < enclen[i]; i2++) {
  86                                 ks4 = crypto1_byte(revstate, 0, 0);
  87                                 printf("%02x", ks4 ^ enc[i][i2]);
  88                                 rollb += 1;
  89                         }
  90                         printf("\n");
  91                 }
  92                 for (int i = 0; i < rollb; i++)
  93                         lfsr_rollback_byte(revstate, 0, 0);
  94         }
  95
  96         lfsr_rollback_word(revstate, 0, 0);
  97         lfsr_rollback_word(revstate, 0, 0);
  98         lfsr_rollback_word(revstate, nr_enc, 1);
  99         lfsr_rollback_word(revstate, uid ^ nt, 0);
 100         crypto1_get_lfsr(revstate, &key);
 101         printf("\nFound Key: [%012"llx"]\n\n", key);
 102         crypto1_destroy(revstate);
 103
 104         t1 = clock() - t1;
 105         if ( t1 > 0 ) printf("Time : %.0f ticks \n", (float)t1);
 106         return 0;
 107 }