tools/nonce2key/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\n", argv[0]);
  17         return 1;
  18     }
  19     sscanf(argv[1], "%08x", &uid);
  20     sscanf(argv[2], "%08x", &nt);
  21     sscanf(argv[3], "%016" SCNx64, &par_info);
  22     sscanf(argv[4], "%016" SCNx64, &ks_info);
  23
  24     // Reset the last three significant bits of the reader nonce
  25     nr &= 0xffffff1f;
  26
  27     printf("\nuid(%08x) nt(%08x) par(%016" PRIx64 ") ks(%016" PRIx64 ")\n\n", uid, nt, par_info, ks_info);
  28
  29     for (pos = 0; pos < 8; pos++) {
  30         ks3x[7 - pos] = (ks_info >> (pos * 8)) & 0x0f;
  31         uint8_t bt = (par_info >> (pos * 8)) & 0xff;
  32
  33         for (uint8_t i = 0; i < 8; i++) {
  34             par[7 - pos][i] = (bt >> i) & 0x01;
  35         }
  36     }
  37
  38     printf("|diff|{nr}    |ks3|ks3^5|parity         |\n");
  39     printf("+----+--------+---+-----+---------------+\n");
  40
  41     for (uint8_t i = 0; i < 8; i++) {
  42         uint32_t nr_diff = nr | i << 5;
  43         printf("| %02x |%08x| %01x |  %01x  |", i << 5, nr_diff, ks3x[i], ks3x[i] ^ 5);
  44
  45         for (pos = 0; pos < 7; pos++)
  46             printf("%01x,", par[i][pos]);
  47         printf("%01x|\n", par[i][7]);
  48     }
  49     printf("+----+--------+---+-----+---------------+\n");
  50
  51     state = lfsr_common_prefix(nr, rr, ks3x, par, false);
  52     lfsr_rollback_word(state, uid ^ nt, 0);
  53     crypto1_get_lfsr(state, &key_recovered);
  54     printf("\nkey recovered: %012" PRIx64 "\n\n", key_recovered);
  55     crypto1_destroy(state);
  56     return 0;
  57 }