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

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <inttypes.h>
   4 #include "crapto1/crapto1.h"
   5 #include "util_posix.h"
   6
   7 int main (int argc, char *argv[])
   8 {
   9         uint32_t uid;     // serial numDber
  10         uint32_t nt;      // tag challenge
  11         uint32_t nr_enc;  // encrypted reader challenge
  12         uint32_t ar_enc;  // encrypted reader response
  13         uint32_t at_enc;  // encrypted tag response
  14         uint64_t key    = 0;                            // recovered key
  15         struct Crypto1State *revstate;
  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 on 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] [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], "%" SCNx32, &uid);
  32         sscanf(argv[2], "%" SCNx32, &nt);
  33         sscanf(argv[3], "%" SCNx32, &nr_enc);
  34         sscanf(argv[4], "%" SCNx32, &ar_enc);
  35         sscanf(argv[5], "%" SCNx32, &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         printf("   uid: %08x\n", uid);
  45         printf("    nt: %08x\n", nt);
  46         printf("  {nr}: %08x\n", nr_enc);
  47         printf("  {ar}: %08x\n", ar_enc);
  48         printf("  {at}: %08x\n", at_enc);
  49         for (int i = 0; i < encc; i++) {
  50                 printf("{enc%d}: ", i);
  51                 for (int i2 = 0; i2 < enclen[i]; i2++) {
  52                         printf("%02x", enc[i][i2]);
  53                 }
  54                 printf("\n");
  55         }
  56
  57         printf("\nLFSR successors of the tag challenge:\n");
  58         printf("  nt' : %08x\n",prng_successor(nt, 64));
  59         printf("  nt'': %08x\n",prng_successor(nt, 96));
  60
  61         // Extract the keystream from the messages
  62         ks2 = ar_enc ^ prng_successor(nt, 64);
  63         ks3 = at_enc ^ prng_successor(nt, 96);
  64
  65         uint64_t start_time = msclock();
  66         revstate = lfsr_recovery64(ks2, ks3);
  67         uint64_t time_spent = msclock() - start_time;
  68         printf("Time spent in lfsr_recovery64(): %1.2f seconds\n", (float)time_spent/1000.0);
  69         printf("\nKeystream used to generate {ar} and {at}:\n");
  70         printf("   ks2: %08x\n",ks2);
  71         printf("   ks3: %08x\n",ks3);
  72
  73         // Decrypting communication using keystream if presented
  74         if (argc > 6 ) {
  75         printf("\nDecrypted communication:\n");
  76         uint8_t ks4;
  77         int rollb = 0;
  78         for (int i = 0; i < encc; i++) {
  79                 printf("{dec%d}: ", i);
  80                 for (int i2 = 0; i2 < enclen[i]; i2++) {
  81                         ks4 = crypto1_byte(revstate, 0, 0);
  82                         printf("%02x", ks4 ^ enc[i][i2]);
  83                         rollb += 1;
  84                 }
  85                 printf("\n");
  86         }
  87         for (int i = 0; i < rollb; i++) {
  88                 lfsr_rollback_byte(revstate, 0, 0);
  89                 }
  90         }
  91
  92         lfsr_rollback_word(revstate, 0, 0);
  93         lfsr_rollback_word(revstate, 0, 0);
  94         lfsr_rollback_word(revstate, nr_enc, 1);
  95         lfsr_rollback_word(revstate, uid ^ nt, 0);
  96         crypto1_get_lfsr(revstate, &key);
  97         crypto1_destroy(revstate);
  98
  99         printf("\nFound Key: [%012" PRIx64"]\n\n",key);
 100
 101 }