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_posix.h"
   8
   9
  10 // 32 bit recover key from 2 nonces
  11 int main (int argc, char *argv[]) {
  12
  13   nonces_t data = {0};
  14   uint32_t ks2;     // keystream used to encrypt reader response
  15   uint64_t key;     // recovered key
  16
  17   printf("MIFARE Classic key recovery - based on 32 bits of keystream\n");
  18   printf("Recover key from two 32-bit reader authentication answers only!\n\n");
  19
  20   if (argc != 7 && argc != 8) {
  21     printf(" syntax: %s <uid> <nt0> <{nr_0}> <{ar_0}> [<nt1>] <{nr_1}> <{ar_1}>\n", argv[0]);
  22         printf("         (you may omit nt1 if it is equal to nt0)\n\n");
  23     return 1;
  24   }
  25
  26   bool moebius_attack = (argc == 8);
  27
  28   sscanf(argv[1],"%x",&data.cuid);
  29   sscanf(argv[2],"%x",&data.nonce);
  30   data.nonce2 = data.nonce;
  31   sscanf(argv[3],"%x",&data.nr);
  32   sscanf(argv[4],"%x",&data.ar);
  33   if (moebius_attack) {
  34           sscanf(argv[5],"%x",&data.nonce2);
  35           sscanf(argv[6],"%x",&data.nr2);
  36           sscanf(argv[7],"%x",&data.ar2);
  37   } else {
  38           sscanf(argv[5],"%x",&data.nr2);
  39           sscanf(argv[6],"%x",&data.ar2);
  40   }
  41
  42   printf("Recovering key for:\n");
  43   printf("    uid: %08x\n",data.cuid);
  44   printf("    nt0: %08x\n",data.nonce);
  45   printf(" {nr_0}: %08x\n",data.nr);
  46   printf(" {ar_0}: %08x\n",data.ar);
  47   printf("    nt1: %08x\n",data.nonce2);
  48   printf(" {nr_1}: %08x\n",data.nr2);
  49   printf(" {ar_1}: %08x\n",data.ar2);
  50
  51   uint64_t start_time = msclock();
  52
  53         // Generate lfsr succesors of the tag challenge
  54   printf("\nLFSR succesors of the tag challenge:\n");
  55   printf("  nt': %08x\n",prng_successor(data.nonce, 64));
  56   printf(" nt'': %08x\n",prng_successor(data.nonce, 96));
  57
  58   // Extract the keystream from the messages
  59   printf("\nKeystream used to generate {ar} and {at}:\n");
  60   ks2 = data.ar ^ prng_successor(data.nonce, 64);
  61   printf("  ks2: %08x\n",ks2);
  62
  63         bool success;
  64         if (moebius_attack) {
  65                 success = mfkey32_moebius(data, &key);
  66         } else {
  67                 success = mfkey32(data, &key);
  68         }
  69
  70         if (success) {
  71                 printf("Recovered key: %012" PRIx64 "\n", key);
  72         } else {
  73                 printf("Couldn't recover key.\n");
  74         }
  75
  76         printf("Time spent: %1.2f seconds\n", (float)(msclock() - start_time)/1000.0);
  77 }