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

   1 #include <inttypes.h>
   2 #include "crapto1/crapto1.h"
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5
   6 int main (int argc, char *argv[]) {
   7   struct Crypto1State *s,*t;
   8   uint64_t key;     // recovered key
   9   uint32_t uid;     // serial number
  10   uint32_t nt;      // tag challenge
  11   uint32_t nr0_enc; // first encrypted reader challenge
  12   uint32_t ar0_enc; // first encrypted reader response
  13   uint32_t nr1_enc; // second encrypted reader challenge
  14   uint32_t ar1_enc; // second encrypted reader response
  15   uint32_t ks2;     // keystream used to encrypt reader response
  16
  17   printf("MIFARE Classic key recovery - based 32 bits of keystream\n");
  18   printf("Recover key from two 32-bit reader authentication answers only!\n\n");
  19
  20   if (argc < 7) {
  21     printf(" syntax: %s <uid> <nt> <{nr_0}> <{ar_0}> <{nr_1}> <{ar_1}>\n\n",argv[0]);
  22     return 1;
  23   }
  24
  25   sscanf(argv[1],"%x",&uid);
  26   sscanf(argv[2],"%x",&nt);
  27   sscanf(argv[3],"%x",&nr0_enc);
  28   sscanf(argv[4],"%x",&ar0_enc);
  29   sscanf(argv[5],"%x",&nr1_enc);
  30   sscanf(argv[6],"%x",&ar1_enc);
  31
  32   printf("Recovering key for:\n");
  33   printf("    uid: %08x\n",uid);
  34   printf("     nt: %08x\n",nt);
  35   printf(" {nr_0}: %08x\n",nr0_enc);
  36   printf(" {ar_0}: %08x\n",ar0_enc);
  37   printf(" {nr_1}: %08x\n",nr1_enc);
  38   printf(" {ar_1}: %08x\n",ar1_enc);
  39
  40         // Generate lfsr succesors of the tag challenge
  41   printf("\nLFSR succesors of the tag challenge:\n");
  42   printf("  nt': %08x\n",prng_successor(nt, 64));
  43   printf(" nt'': %08x\n",prng_successor(nt, 96));
  44
  45   // Extract the keystream from the messages
  46   printf("\nKeystream used to generate {ar} and {at}:\n");
  47   ks2 = ar0_enc ^ prng_successor(nt, 64);
  48   printf("  ks2: %08x\n",ks2);
  49
  50         s = lfsr_recovery32(ar0_enc ^ prng_successor(nt, 64), 0);
  51
  52         for(t = s; t->odd | t->even; ++t) {
  53                 lfsr_rollback_word(t, 0, 0);
  54                 lfsr_rollback_word(t, nr0_enc, 1);
  55                 lfsr_rollback_word(t, uid ^ nt, 0);
  56                 crypto1_get_lfsr(t, &key);
  57                 crypto1_word(t, uid ^ nt, 0);
  58                 crypto1_word(t, nr1_enc, 1);
  59                 if (ar1_enc == (crypto1_word(t, 0, 0) ^ prng_successor(nt, 64))) {
  60                         printf("\nFound Key: [%012" PRIx64 "]\n\n",key);
  61                         break;
  62                 }
  63         }
  64   free(s);
  65
  66   return 0;
  67 }