tools/mfc/card_only/nonce2key.c

   1 #include "crapto1/crapto1.h"
   2 #define __STDC_FORMAT_MACROS
   3 #include <inttypes.h>
   4 #include <stdio.h>
   5
   6 int main(const int argc, const char *argv[]) {
   7     struct Crypto1State *state;
   8     uint32_t pos, uid, nt, nr, rr;
   9     uint8_t ks3x[8], par[8][8];
  10     uint64_t key_recovered;
  11     uint64_t par_info;
  12     uint64_t ks_info;
  13     nr = rr = 0;
  14
  15     if (argc < 5) {
  16         printf("\nsyntax:  %s <uid> <nt> <par> <ks>\n", argv[0]);
  17         printf("example: %s 92c0456b 73294ab7 a3fbfb537343eb7b 070608090e060a02\n\n", argv[0]);
  18         return 1;
  19     }
  20     sscanf(argv[1], "%08x", &uid);
  21     sscanf(argv[2], "%08x", &nt);
  22     sscanf(argv[3], "%016" SCNx64, &par_info);
  23     sscanf(argv[4], "%016" SCNx64, &ks_info);
  24
  25     // Reset the last three significant bits of the reader nonce
  26     nr &= 0xffffff1f;
  27
  28     printf("\nuid(%08x) nt(%08x) par(%016" PRIx64 ") ks(%016" PRIx64 ")\n\n", uid, nt, par_info, ks_info);
  29
  30     for (pos = 0; pos < 8; pos++) {
  31         ks3x[7 - pos] = (ks_info >> (pos * 8)) & 0x0f;
  32         uint8_t bt = (par_info >> (pos * 8)) & 0xff;
  33
  34         for (uint8_t i = 0; i < 8; i++) {
  35             par[7 - pos][i] = (bt >> i) & 0x01;
  36         }
  37     }
  38
  39     printf("|diff|{nr}    |ks3|ks3^5|parity         |\n");
  40     printf("+----+--------+---+-----+---------------+\n");
  41
  42     for (uint8_t i = 0; i < 8; i++) {
  43         uint32_t nr_diff = nr | i << 5;
  44         printf("| %02x |%08x| %01x |  %01x  |", i << 5, nr_diff, ks3x[i], ks3x[i] ^ 5);
  45
  46         for (pos = 0; pos < 7; pos++)
  47             printf("%01x,", par[i][pos]);
  48         printf("%01x|\n", par[i][7]);
  49     }
  50     printf("+----+--------+---+-----+---------------+\n");
  51
  52     state = lfsr_common_prefix(nr, rr, ks3x, par, false);
  53     lfsr_rollback_word(state, uid ^ nt, 0);
  54     crypto1_get_lfsr(state, &key_recovered);
  55     printf("\nkey recovered: %012" PRIx64 "\n\n", key_recovered);
  56     crypto1_destroy(state);
  57     return 0;
  58 }