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

   1 #include <inttypes.h>
   2 #include <stdbool.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include "crapto1/crapto1.h"
   6 #include "mfkey.h"
   7 #include "util.h"
   8
   9 // 32 bit recover key from 2 nonces
  10 int main (int argc, char *argv[]) {
  11
  12   nonces_t data;
  13   uint32_t ks2;     // keystream used to encrypt reader response
  14   uint64_t key;     // recovered key
  15
  16   printf("MIFARE Classic key recovery - based on 32 bits of keystream\n");
  17   printf("Recover key from two 32-bit reader authentication answers only!\n\n");
  18
  19   if (argc != 7 && argc != 8) {
  20     printf(" syntax: %s <uid> <nt0> <{nr_0}> <{ar_0}> [<nt1>] <{nr_1}> <{ar_1}>\n", argv[0]);
  21         printf("         (you may omit nt1 if it is equal to nt0)\n\n");
  22     return 1;
  23   }
  24
  25   bool moebius_attack = (argc == 8);
  26
  27   sscanf(argv[1],"%x",&data.cuid);
  28   sscanf(argv[2],"%x",&data.nonce);
  29   data.nonce2 = data.nonce;
  30   sscanf(argv[3],"%x",&data.nr);
  31   sscanf(argv[4],"%x",&data.ar);
  32   if (moebius_attack) {
  33           sscanf(argv[5],"%x",&data.nonce2);
  34           sscanf(argv[6],"%x",&data.nr2);
  35           sscanf(argv[7],"%x",&data.ar2);
  36   } else {
  37           sscanf(argv[5],"%x",&data.nr2);
  38           sscanf(argv[6],"%x",&data.ar2);
  39   }
  40
  41   printf("Recovering key for:\n");
  42   printf("    uid: %08x\n",data.cuid);
  43   printf("    nt0: %08x\n",data.nonce);
  44   printf(" {nr_0}: %08x\n",data.nr);
  45   printf(" {ar_0}: %08x\n",data.ar);
  46   printf("    nt1: %08x\n",data.nonce2);
  47   printf(" {nr_1}: %08x\n",data.nr2);
  48   printf(" {ar_1}: %08x\n",data.ar2);
  49
  50   uint64_t start_time = msclock();
  51
  52         // Generate lfsr succesors of the tag challenge
  53   printf("\nLFSR succesors of the tag challenge:\n");
  54   printf("  nt': %08x\n",prng_successor(data.nonce, 64));
  55   printf(" nt'': %08x\n",prng_successor(data.nonce, 96));
  56
  57   // Extract the keystream from the messages
  58   printf("\nKeystream used to generate {ar} and {at}:\n");
  59   ks2 = data.ar ^ prng_successor(data.nonce, 64);
  60   printf("  ks2: %08x\n",ks2);
  61
  62         bool success;
  63         if (moebius_attack) {
  64                 success = mfkey32_moebius(data, &key);
  65         } else {
  66                 success = mfkey32(data, &key);
  67         }
  68
  69         if (success) {
  70                 printf("Recovered key: %012" PRIx64 "\n", key);
  71         } else {
  72                 printf("Couldn't recover key.\n");
  73         }
  74
  75         printf("Time spent: %1.2f seconds\n", (float)(msclock() - start_time)/1000.0);
  76 }