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