git.zerfleddert.de Git - proxmark3-svn/blob - tools/mfkey/mfkey32.c

   1 #define __STDC_FORMAT_MACROS
   2 #include <inttypes.h>
   3 #include "crapto1.h"
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <time.h>
   7
   8 #define llx PRIx64
   9 #define lli PRIi64
  10 int main (int argc, char *argv[]) {
  11         struct Crypto1State *s,*t;
  12         uint64_t key;     // recovered key
  13         uint32_t uid;     // serial number
  14         uint32_t nt;      // tag challenge
  15         uint32_t nr0_enc; // first encrypted reader challenge
  16         uint32_t ar0_enc; // first encrypted reader response
  17         uint32_t nr1_enc; // second encrypted reader challenge
  18         uint32_t ar1_enc; // second encrypted reader response
  19         uint32_t ks2;     // keystream used to encrypt reader response
  20
  21         printf("MIFARE Classic key recovery - based 32 bits of keystream\n");
  22         printf("Recover key from two 32-bit reader authentication answers only!\n\n");
  23
  24         if (argc < 7) {
  25                 printf(" syntax: %s <uid> <nt> <nr_0> <ar_0> <nr_1> <ar_1>\n\n",argv[0]);
  26                 return 1;
  27         }
  28
  29         sscanf(argv[1],"%x",&uid);
  30         sscanf(argv[2],"%x",&nt);
  31         sscanf(argv[3],"%x",&nr0_enc);
  32         sscanf(argv[4],"%x",&ar0_enc);
  33         sscanf(argv[5],"%x",&nr1_enc);
  34         sscanf(argv[6],"%x",&ar1_enc);
  35
  36         printf("Recovering key for:\n");
  37         printf("    uid: %08x\n",uid);
  38         printf("     nt: %08x\n",nt);
  39         printf(" {nr_0}: %08x\n",nr0_enc);
  40         printf(" {ar_0}: %08x\n",ar0_enc);
  41         printf(" {nr_1}: %08x\n",nr1_enc);
  42         printf(" {ar_1}: %08x\n",ar1_enc);
  43
  44         // Generate lfsr succesors of the tag challenge
  45         printf("\nLFSR succesors of the tag challenge:\n");
  46         uint32_t p64 = prng_successor(nt, 64);
  47         printf("  nt': %08x\n", p64);
  48         printf(" nt'': %08x\n", prng_successor(p64, 32));
  49
  50         clock_t t1 = clock();
  51
  52         // Extract the keystream from the messages
  53         printf("\nKeystream used to generate {ar} and {at}:\n");
  54         ks2 = ar0_enc ^ p64;
  55         printf("  ks2: %08x\n", ks2);
  56
  57         s = lfsr_recovery32(ar0_enc ^ p64, 0);
  58
  59         for(t = s; t->odd | t->even; ++t) {
  60                 lfsr_rollback_word(t, 0, 0);
  61                 lfsr_rollback_word(t, nr0_enc, 1);
  62                 lfsr_rollback_word(t, uid ^ nt, 0);
  63                 crypto1_get_lfsr(t, &key);
  64                 crypto1_word(t, uid ^ nt, 0);
  65                 crypto1_word(t, nr1_enc, 1);
  66                 if (ar1_enc == (crypto1_word(t, 0, 0) ^ p64)) {
  67                         printf("\nFound Key: [%012"llx"]\n\n",key);
  68                         break;}
  69         }
  70         free(s);
  71         t1 = clock() - t1;
  72         if ( t1 > 0 ) printf("Time : %.0f ticks \n", (float)t1);
  73         return 0;
  74 }